diff --git a/app/src/main/app/shell/UnifiedActivity.kt b/app/src/main/app/shell/UnifiedActivity.kt
index e94f5775d..f5597a84d 100644
--- a/app/src/main/app/shell/UnifiedActivity.kt
+++ b/app/src/main/app/shell/UnifiedActivity.kt
@@ -7656,7 +7656,9 @@ class UnifiedActivity :
             } catch (e: Exception) {
                 0L
             }
-        val isInstallEnabled = installed || totalInstallSize == 0L || availableBytes >= totalInstallSize
+        // Installed game: base content is on disk, so only gate on the newly-selected DLC bytes.
+        val requiredBytes = if (installed) selectedDlcInstallBytes else totalInstallSize
+        val isInstallEnabled = requiredBytes == 0L || availableBytes >= requiredBytes
         val installActionEnabled = isInstallEnabled && !hasBlockingEpicDownload
         val installPathDisplay = if (installed) app.installPath else (customPath ?: EpicConstants.defaultEpicGamesPath(context))
 
@@ -9927,6 +9929,7 @@ class UnifiedActivity :
         val context = LocalContext.current
         var isLoading by remember { mutableStateOf(true) }
         var selectedManifestSizes by remember { mutableStateOf(SteamService.ManifestSizes()) }
+        var baseInstallSize by remember(app.id) { mutableStateOf(0L) }
         var dlcApps by remember { mutableStateOf<List<SteamApp>>(emptyList()) }
         var dlcSizes by remember { mutableStateOf<Map<Int, SteamService.ManifestSizes>>(emptyMap()) }
         var installedDlcIds by remember(app.id) { mutableStateOf<Set<Int>>(emptySet()) }
@@ -9992,6 +9995,7 @@ class UnifiedActivity :
             installedDlcIds = loadData.installedDlcIds
             selectedDlcIds.removeAll(loadData.installedDlcIds)
             selectedManifestSizes = loadData.baseManifestSizes
+            baseInstallSize = loadData.baseManifestSizes.installSize
             installed = loadData.installed
             isLoading = false
         }
@@ -10019,7 +10023,11 @@ class UnifiedActivity :
             } catch (e: Exception) {
                 0L
             }
-        val isInstallEnabled = totalInstallSize == 0L || availableBytes >= totalInstallSize
+        // For an already-installed game the base content is on disk, so only require free
+        // space for the newly-selected DLC (already-installed DLC is excluded from selection).
+        val requiredBytes =
+            if (installed == true) (totalInstallSize - baseInstallSize).coerceAtLeast(0L) else totalInstallSize
+        val isInstallEnabled = requiredBytes == 0L || availableBytes >= requiredBytes
         val installPathDisplay = customPath ?: SteamService.defaultAppInstallPath
 
         val dlcItems =
diff --git a/app/src/main/assets/wnsteam/bionic/steam.exe b/app/src/main/assets/wnsteam/bionic/steam.exe
index 7260a95f5..1b6d8a125 100755
Binary files a/app/src/main/assets/wnsteam/bionic/steam.exe and b/app/src/main/assets/wnsteam/bionic/steam.exe differ
diff --git a/app/src/main/cpp/wn-steam-launcher/src/main.cpp b/app/src/main/cpp/wn-steam-launcher/src/main.cpp
index e452cf14a..6fd88401b 100644
--- a/app/src/main/cpp/wn-steam-launcher/src/main.cpp
+++ b/app/src/main/cpp/wn-steam-launcher/src/main.cpp
@@ -231,6 +231,24 @@ static void stage_steam_config(void) {
     }
 }
 
+// Escape a free-text value for a VDF/ACF quoted field: double backslashes, then
+// escape quotes and newlines. Mirrors the Kotlin escapeString() so the C++ and
+// Kotlin manifest paths produce identical, well-formed output.
+static std::string vdf_escape(const char* s) {
+    std::string out;
+    if (!s) return out;
+    for (const char* p = s; *p; ++p) {
+        switch (*p) {
+            case '\\': out += "\\\\"; break;
+            case '"':  out += "\\\""; break;
+            case '\n': out += "\\n"; break;
+            case '\r': out += "\\r"; break;
+            default:   out += *p; break;
+        }
+    }
+    return out;
+}
+
 static void stage_app_manifest(uint32_t appId, const char* gameExe) {
     if (appId == 0 || !gameExe) return;
     const char* marker = "\\steamapps\\common\\";
@@ -258,33 +276,155 @@ static void stage_app_manifest(uint32_t appId, const char* gameExe) {
     snprintf(acf, sizeof(acf),
              "C:\\Program Files (x86)\\Steam\\steamapps\\appmanifest_%u.acf",
              appId);
+    const char* owner = getenv("WN_STEAM_STEAMID");
+    const char* depotsEnv = getenv("WN_STEAM_DEPOTS");
+    const char* sharedEnv = getenv("WN_STEAM_SHARED_DEPOTS");
+    const char* appName = getenv("WN_STEAM_APP_NAME");
+    const char* installScriptsEnv = getenv("WN_STEAM_INSTALL_SCRIPTS");
+    const char* language = getenv("WN_STEAM_LANGUAGE");
+    const char* buildIdStr = getenv("WN_STEAM_BUILD_ID");
+    const char* sizeOnDiskStr = getenv("WN_STEAM_SIZE_ON_DISK");
+    const char* bytesToDownloadStr = getenv("WN_STEAM_BYTES_TO_DOWNLOAD");
+    const char* bytesToStageStr = getenv("WN_STEAM_BYTES_TO_STAGE");
+    if (!appName || !*appName) appName = installdir;
+    if (!language || !*language) language = "english";
+    unsigned long long buildId = (buildIdStr && *buildIdStr) ? strtoull(buildIdStr, NULL, 10) : 0ULL;
+    unsigned long long sizeOnDisk = (sizeOnDiskStr && *sizeOnDiskStr) ? strtoull(sizeOnDiskStr, NULL, 10) : 0ULL;
+    unsigned long long bytesToDownload = (bytesToDownloadStr && *bytesToDownloadStr) ? strtoull(bytesToDownloadStr, NULL, 10) : 0ULL;
+    unsigned long long bytesToStage = (bytesToStageStr && *bytesToStageStr) ? strtoull(bytesToStageStr, NULL, 10) : 0ULL;
     FILE* f = fopen(acf, "w");
     if (!f) {
         log_line("[wn-launcher] app manifest: fopen(%s) failed", acf);
         return;
     }
-    const char* owner = getenv("WN_STEAM_STEAMID");
+    std::string nameEsc = vdf_escape(appName);
+    std::string installdirEsc = vdf_escape(installdir);
+    std::string languageEsc = vdf_escape(language);
     fprintf(f,
             "\"AppState\"\n"
             "{\n"
             "\t\"appid\"\t\t\"%u\"\n"
-            "\t\"Universe\"\t\t\"1\"\n"
+            "\t\"universe\"\t\t\"1\"\n"
+            "\t\"LauncherPath\"\t\t\"C:\\\\Program Files (x86)\\\\Steam\\\\steam.exe\"\n"
             "\t\"name\"\t\t\"%s\"\n"
             "\t\"StateFlags\"\t\t\"4\"\n"
             "\t\"installdir\"\t\t\"%s\"\n"
-            "\t\"LastUpdated\"\t\t\"0\"\n"
-            "\t\"SizeOnDisk\"\t\t\"0\"\n"
-            "\t\"buildid\"\t\t\"0\"\n"
+            "\t\"LastUpdated\"\t\t\"%llu\"\n"
+            "\t\"LastPlayed\"\t\t\"0\"\n"
+            "\t\"SizeOnDisk\"\t\t\"%llu\"\n"
+            "\t\"StagingSize\"\t\t\"0\"\n"
+            "\t\"buildid\"\t\t\"%llu\"\n"
             "\t\"LastOwner\"\t\t\"%s\"\n"
-            "\t\"InstalledDepots\"\n"
+            "\t\"DownloadType\"\t\t\"1\"\n"
+            "\t\"UpdateResult\"\t\t\"0\"\n"
+            "\t\"BytesToDownload\"\t\t\"%llu\"\n"
+            "\t\"BytesDownloaded\"\t\t\"%llu\"\n"
+            "\t\"BytesToStage\"\t\t\"%llu\"\n"
+            "\t\"BytesStaged\"\t\t\"%llu\"\n"
+            "\t\"TargetBuildID\"\t\t\"%llu\"\n"
+            "\t\"AutoUpdateBehavior\"\t\t\"0\"\n"
+            "\t\"AllowOtherDownloadsWhileRunning\"\t\t\"0\"\n"
+            "\t\"ScheduledAutoUpdate\"\t\t\"0\"\n",
+            appId, nameEsc.c_str(), installdirEsc.c_str(),
+            (unsigned long long)time(NULL),
+            sizeOnDisk, buildId,
+            (owner && *owner) ? owner : "0",
+            bytesToDownload, bytesToDownload,
+            bytesToStage, bytesToStage, buildId);
+    // Write InstalledDepots with depot data from WN_STEAM_DEPOTS env var.
+    // Format: depotId:manifestGid:size[:dlcAppId],...
+    if (depotsEnv && *depotsEnv) {
+        fprintf(f, "\t\"InstalledDepots\"\n\t{\n");
+        std::vector<char> buf(strlen(depotsEnv) + 1);
+        memcpy(buf.data(), depotsEnv, buf.size());
+        char* token = strtok(buf.data(), ",");
+        while (token) {
+            // Parse depotId:manifestGid:size[:dlcAppId]
+            char* colon1 = strchr(token, ':');
+            if (!colon1) { token = strtok(NULL, ","); continue; }
+            *colon1 = '\0';
+            const char* depotIdStr = token;
+            char* manifestStart = colon1 + 1;
+            char* colon2 = strchr(manifestStart, ':');
+            if (!colon2) { token = strtok(NULL, ","); continue; }
+            *colon2 = '\0';
+            const char* manifestStr = manifestStart;
+            char* sizeStart = colon2 + 1;
+            char* colon3 = strchr(sizeStart, ':');
+            const char* sizeStr, *dlcAppIdStr;
+            if (colon3) {
+                *colon3 = '\0';
+                sizeStr = sizeStart;
+                dlcAppIdStr = colon3 + 1;
+            } else {
+                sizeStr = sizeStart;
+                dlcAppIdStr = NULL;
+            }
+            fprintf(f, "\t\t\"%s\"\n\t\t{\n"
+                       "\t\t\t\"manifest\"\t\t\"%s\"\n"
+                       "\t\t\t\"size\"\t\t\"%s\"\n",
+                    depotIdStr, manifestStr, sizeStr);
+            if (dlcAppIdStr && *dlcAppIdStr) {
+                fprintf(f, "\t\t\t\"dlcappid\"\t\t\"%s\"\n", dlcAppIdStr);
+            }
+            fprintf(f, "\t\t}\n");
+            token = strtok(NULL, ",");
+        }
+        fprintf(f, "\t}\n");
+    } else {
+        fprintf(f, "\t\"InstalledDepots\"\n\t{\n\t}\n");
+    }
+    // Write InstallScripts from WN_STEAM_INSTALL_SCRIPTS env var.
+    // Format: depotId:scriptFilename,...
+    if (installScriptsEnv && *installScriptsEnv) {
+        fprintf(f, "\t\"InstallScripts\"\n\t{\n");
+        std::vector<char> isbuf(strlen(installScriptsEnv) + 1);
+        memcpy(isbuf.data(), installScriptsEnv, isbuf.size());
+        char* istoken = strtok(isbuf.data(), ",");
+        while (istoken) {
+            char* iscolon = strchr(istoken, ':');
+            if (!iscolon) { istoken = strtok(NULL, ","); continue; }
+            *iscolon = '\0';
+            std::string scriptEsc = vdf_escape(iscolon + 1);
+            fprintf(f, "\t\t\"%s\"\t\t\"%s\"\n", istoken, scriptEsc.c_str());
+            istoken = strtok(NULL, ",");
+        }
+        fprintf(f, "\t}\n");
+    }
+    // Write SharedDepots from WN_STEAM_SHARED_DEPOTS env var.
+    // Format: sourceDepotId:targetAppId,...
+    if (sharedEnv && *sharedEnv) {
+        fprintf(f, "\t\"SharedDepots\"\n\t{\n");
+        std::vector<char> sbuf(strlen(sharedEnv) + 1);
+        memcpy(sbuf.data(), sharedEnv, sbuf.size());
+        char* stoken = strtok(sbuf.data(), ",");
+        while (stoken) {
+            char* scolon = strchr(stoken, ':');
+            if (!scolon) { stoken = strtok(NULL, ","); continue; }
+            *scolon = '\0';
+            fprintf(f, "\t\t\"%s\"\t\t\"%s\"\n", stoken, scolon + 1);
+            stoken = strtok(NULL, ",");
+        }
+        fprintf(f, "\t}\n");
+    }
+    fprintf(f,
+            "\t\"UserConfig\"\n"
+            "\t{\n"
+            "\t\t\"language\"\t\t\"%s\"\n"
+            "\t}\n"
+            "\t\"MountedConfig\"\n"
             "\t{\n"
+            "\t\t\"language\"\t\t\"%s\"\n"
             "\t}\n"
             "}\n",
-            appId, installdir, installdir,
-            (owner && *owner) ? owner : "0");
+            languageEsc.c_str(), languageEsc.c_str());
     fclose(f);
-    log_line("[wn-launcher] app manifest staged: %s (installdir=\"%s\", StateFlags=4)",
-             acf, installdir);
+    log_line("[wn-launcher] app manifest staged: %s (installdir=\"%s\", "
+             "depots=%s shared=%s scripts=%s)",
+             acf, installdir,
+             depotsEnv && *depotsEnv ? depotsEnv : "(none)",
+             sharedEnv && *sharedEnv ? sharedEnv : "(none)",
+             installScriptsEnv && *installScriptsEnv ? installScriptsEnv : "(none)");
 }
 
 // Counts running game processes (matches LaunchApp's canonical name or the literal
diff --git a/app/src/main/feature/settings/stores/StoresFragment.kt b/app/src/main/feature/settings/stores/StoresFragment.kt
index 1f6c5e0e9..d4633c1d2 100644
--- a/app/src/main/feature/settings/stores/StoresFragment.kt
+++ b/app/src/main/feature/settings/stores/StoresFragment.kt
@@ -25,6 +25,7 @@ import com.winlator.cmod.feature.stores.gog.service.GOGAuthManager
 import com.winlator.cmod.feature.stores.gog.service.GOGService
 import com.winlator.cmod.feature.stores.gog.ui.auth.GOGOAuthActivity
 import com.winlator.cmod.feature.stores.steam.SteamLoginActivity
+import com.winlator.cmod.feature.stores.steam.enums.Language
 import com.winlator.cmod.feature.stores.steam.service.SteamService
 import com.winlator.cmod.feature.stores.steam.utils.PrefManager
 import com.winlator.cmod.shared.android.DirectoryPickerDialog
@@ -150,6 +151,11 @@ class StoresFragment : Fragment() {
                         onPickSteamFolder = { pickFolder(PrefManager.steamDownloadFolder) { PrefManager.steamDownloadFolder = it } },
                         onPickEpicFolder = { pickFolder(PrefManager.epicDownloadFolder) { PrefManager.epicDownloadFolder = it } },
                         onPickGogFolder = { pickFolder(PrefManager.gogDownloadFolder) { PrefManager.gogDownloadFolder = it } },
+                        onContainerLanguageSelected = { index ->
+                            val langName = Language.containerLangForIndex(index)
+                            PrefManager.containerLanguage = langName
+                            refresh()
+                        },
                         bridge = (requireActivity() as? UnifiedActivity)?.settingsNavBridge,
                     )
                 }
@@ -165,6 +171,8 @@ class StoresFragment : Fragment() {
     // Helpers
     private fun refresh() {
         val ctx = context ?: return
+        val containerLanguageLabels = Language.displayLabels()
+        val containerLanguageIndex = Language.indexForContainerLang(PrefManager.containerLanguage)
         storeState =
             StoreState(
                 isSteamLoggedIn = SteamService.isLoggedIn,
@@ -178,6 +186,8 @@ class StoresFragment : Fragment() {
                 steamFolder = resolveUri(PrefManager.steamDownloadFolder, ctx),
                 epicFolder = resolveUri(PrefManager.epicDownloadFolder, ctx),
                 gogFolder = resolveUri(PrefManager.gogDownloadFolder, ctx),
+                containerLanguageLabels = containerLanguageLabels,
+                containerLanguageIndex = containerLanguageIndex,
             )
     }
 
diff --git a/app/src/main/feature/settings/stores/StoresScreen.kt b/app/src/main/feature/settings/stores/StoresScreen.kt
index e2d2ae872..56e414afe 100644
--- a/app/src/main/feature/settings/stores/StoresScreen.kt
+++ b/app/src/main/feature/settings/stores/StoresScreen.kt
@@ -44,6 +44,7 @@ import androidx.compose.material.icons.outlined.Folder
 import androidx.compose.material.icons.outlined.FolderShared
 import androidx.compose.material.icons.outlined.Gamepad
 import androidx.compose.material.icons.outlined.KeyboardArrowDown
+import androidx.compose.material.icons.outlined.Language
 import androidx.compose.material.icons.outlined.Public
 import androidx.compose.material.icons.outlined.Speed
 import androidx.compose.material.icons.outlined.Wifi
@@ -109,6 +110,8 @@ data class StoreState(
     val steamFolder: String = "",
     val epicFolder: String = "",
     val gogFolder: String = "",
+    val containerLanguageLabels: List<String> = emptyList(),
+    val containerLanguageIndex: Int = 0,
 )
 
 @Composable
@@ -128,6 +131,7 @@ fun StoresScreen(
     onPickSteamFolder: () -> Unit,
     onPickEpicFolder: () -> Unit,
     onPickGogFolder: () -> Unit,
+    onContainerLanguageSelected: (Int) -> Unit,
     bridge: SettingsNavBridge? = null,
 ) {
     val layoutDirection = LocalLayoutDirection.current
@@ -258,6 +262,18 @@ fun StoresScreen(
                 onOptionSelected = onDownloadServerChanged,
             )
 
+            val gameLanguageOptions = remember(state.containerLanguageLabels) {
+                state.containerLanguageLabels.mapIndexed { index, label -> index to label }
+            }
+            SettingsDropdownCard(
+                title = stringResource(R.string.settings_other_game_language_title),
+                subtitle = stringResource(R.string.settings_other_game_language_summary),
+                icon = Icons.Outlined.Language,
+                selectedValue = state.containerLanguageIndex,
+                options = gameLanguageOptions,
+                onOptionSelected = onContainerLanguageSelected,
+            )
+
             Spacer(Modifier.height(24.dp + navBarBottomPadding))
         }
     }
diff --git a/app/src/main/feature/stores/steam/enums/Language.kt b/app/src/main/feature/stores/steam/enums/Language.kt
index 64f8f77be..8477e0294 100644
--- a/app/src/main/feature/stores/steam/enums/Language.kt
+++ b/app/src/main/feature/stores/steam/enums/Language.kt
@@ -1,35 +1,53 @@
 package com.winlator.cmod.feature.stores.steam.enums
 import timber.log.Timber
 
-enum class Language {
-    english,
-    german,
-    french,
-    italian,
-    koreana,
-    spanish,
-    schinese,
-    sc_schinese,
-    tchinese,
-    russian,
-    japanese,
-    polish,
-    brazilian,
-    latam,
-    vietnamese,
-    portuguese,
-    danish,
-    dutch,
-    swedish,
-    norwegian,
-    finnish,
-    turkish,
-    thai,
-    czech,
-    unknown,
+enum class Language(val displayName: String) {
+    english("English"),
+    german("German"),
+    french("French"),
+    italian("Italian"),
+    koreana("Korean"),
+    spanish("Spanish"),
+    schinese("Simplified Chinese"),
+    sc_schinese("Simplified Chinese (SC)"),
+    tchinese("Traditional Chinese"),
+    russian("Russian"),
+    japanese("Japanese"),
+    polish("Polish"),
+    brazilian("Portuguese (Brazil)"),
+    latam("Spanish (Latin America)"),
+    vietnamese("Vietnamese"),
+    portuguese("Portuguese"),
+    danish("Danish"),
+    dutch("Dutch"),
+    swedish("Swedish"),
+    norwegian("Norwegian"),
+    finnish("Finnish"),
+    turkish("Turkish"),
+    thai("Thai"),
+    czech("Czech"),
+    unknown("Unknown"),
     ;
 
     companion object {
+        /** All display names in enum order, excluding [unknown] and the non-standard [sc_schinese] duplicate. */
+        fun displayLabels(): List<String> =
+            entries.filter { it != unknown && it != sc_schinese }.map { it.displayName }
+
+        /** Index of the entry whose [name] matches [containerLang], or the index of [english] as fallback. */
+        fun indexForContainerLang(containerLang: String?): Int {
+            val code = containerLang?.lowercase() ?: return 0
+            val filtered = entries.filter { it != unknown && it != sc_schinese }
+            val match = filtered.indexOfFirst { it.name == code }
+            return if (match >= 0) match else 0
+        }
+
+        /** Container language enum name for a given display-name [index] (0-based into the filtered list). */
+        fun containerLangForIndex(index: Int): String {
+            val filtered = entries.filter { it != unknown && it != sc_schinese }
+            return filtered.getOrNull(index)?.name ?: english.name
+        }
+
         fun from(keyValue: String?): Language =
             when (keyValue?.lowercase()) {
                 english.name -> {
diff --git a/app/src/main/feature/stores/steam/service/SteamService.kt b/app/src/main/feature/stores/steam/service/SteamService.kt
index 665e65695..87d53d0f7 100644
--- a/app/src/main/feature/stores/steam/service/SteamService.kt
+++ b/app/src/main/feature/stores/steam/service/SteamService.kt
@@ -4173,6 +4173,7 @@ class SteamService : Service() {
                         .distinct(),
                 )
             }
+            mainAppDlcIds.addAll(calculatedDlcAppIds.filter { it !in mainAppDlcIds })
 
             runBlocking(Dispatchers.IO) {
                 if (mainAppDepots.isNotEmpty()) {
diff --git a/app/src/main/feature/stores/steam/utils/SteamUtils.kt b/app/src/main/feature/stores/steam/utils/SteamUtils.kt
index 0b022ffa0..40c66427b 100644
--- a/app/src/main/feature/stores/steam/utils/SteamUtils.kt
+++ b/app/src/main/feature/stores/steam/utils/SteamUtils.kt
@@ -17,6 +17,7 @@ import com.winlator.cmod.runtime.wine.WineUtils
 import com.winlator.cmod.runtime.wine.WineRegistryEditor
 import com.winlator.cmod.feature.stores.steam.enums.EOSType
 import com.winlator.cmod.feature.stores.steam.enums.EPersonaState
+import com.winlator.cmod.feature.stores.steam.service.SteamService.Companion.getOwnedAppDlc
 import kotlinx.coroutines.runBlocking
 import okhttp3.Call
 import okhttp3.Callback
@@ -814,15 +815,33 @@ object SteamUtils {
         branch: String,
         installedDepotIds: Set<Int>,
         installedDlcAppIds: Set<Int>,
+        language: String,
     ): LinkedHashMap<Int, ManifestInfo> {
         val allKnownDepots = linkedMapOf<Int, DepotInfo>()
         appInfo.depots.forEach { (depotId, depot) -> allKnownDepots[depotId] = depot }
-        SteamService.getDownloadableDepots(steamAppId).forEach { (depotId, depot) ->
+        SteamService.getDownloadableDepots(steamAppId, language).forEach { (depotId, depot) ->
             allKnownDepots[depotId] = depot
         }
 
+        val installedDlcDepotsIds = SteamService.getInstalledDlcDepotsOf(steamAppId)
+        installedDlcDepotsIds?.forEach { appId ->
+            try {
+                runBlocking {
+                    getOwnedAppDlc(appId).forEach { (depotId, depot) ->
+                        allKnownDepots[depotId] = depot
+                    }
+                }
+            } catch (e: Exception) {
+                Timber.w(e, "Failed to resolve owned DLC depots for appId=$appId")
+            }
+        }
+
+
         val installedDepots = linkedMapOf<Int, ManifestInfo>()
         allKnownDepots.forEach { (depotId, depotInfo) ->
+            // Exclude shared depots from InstalledDepots — they belong in SharedDepots only
+            if (depotInfo.sharedInstall) return@forEach
+
             val shouldInclude =
                 depotId in installedDepotIds ||
                     (
@@ -839,9 +858,11 @@ object SteamUtils {
     }
 
     @JvmStatic
+    @JvmOverloads
     fun createAppManifest(
         context: Context,
         steamAppId: Int,
+        language: String = "english",
     ) {
         try {
             Timber.i("Attempting to createAppManifest for appId: $steamAppId")
@@ -890,26 +911,68 @@ object SteamUtils {
                     branch = selectedBranch,
                     installedDepotIds = installedDepotIds,
                     installedDlcAppIds = installedDlcAppIds,
+                    language = language,
                 )
 
+            // Compute total download and stage sizes from resolved depots
+            val totalBytesToDownload = installedDepots.values.sumOf { it.download }
+            val totalBytesToStage = installedDepots.values.sumOf { it.size }
+
+            // Collect dlcAppId mapping for InstalledDepots entries
+            val allKnownDepots = linkedMapOf<Int, com.winlator.cmod.feature.stores.steam.data.DepotInfo>()
+            appInfo.depots.forEach { (depotId, depot) -> allKnownDepots[depotId] = depot }
+            SteamService.getDownloadableDepots(steamAppId, language).forEach { (depotId, depot) ->
+                allKnownDepots[depotId] = depot
+            }
+
+            // Collect shared depots for SharedDepots section
+            val sharedDepots = linkedMapOf<Int, Int>()
+            allKnownDepots.forEach { (depotId, depotInfo) ->
+                if (depotInfo.sharedInstall && depotInfo.depotFromApp != SteamService.INVALID_APP_ID) {
+                    sharedDepots[depotId] = depotInfo.depotFromApp
+                }
+            }
+
+            // Collect install scripts for InstallScripts section
+            val installScripts = linkedMapOf<Int, String>()
+            if (appInfo.installScript.isNotBlank()) {
+                // Map the base game depot(s) to the install script (base app's own depots only,
+                // matching the native launcher env-var path in XServerDisplayActivity).
+                appInfo.depots.forEach { (depotId, depotInfo) ->
+                    if (depotInfo.dlcAppId == SteamService.INVALID_APP_ID &&
+                        depotInfo.depotFromApp == SteamService.INVALID_APP_ID
+                    ) {
+                        installScripts[depotId] = appInfo.installScript
+                    }
+                }
+            }
+
             val acfContent =
                 buildString {
                     appendLine("\"AppState\"")
                     appendLine("{")
                     appendLine("\t\"appid\"\t\t\"$steamAppId\"")
-                    appendLine("\t\"Universe\"\t\t\"1\"")
+                    appendLine("\t\"universe\"\t\t\"1\"")
+                    appendLine("\t\"LauncherPath\"\t\t\"C:\\\\Program Files (x86)\\\\Steam\\\\steam.exe\"")
                     appendLine("\t\"name\"\t\t\"${escapeString(appInfo.name)}\"")
                     appendLine("\t\"StateFlags\"\t\t\"4\"")
-                    appendLine("\t\"LastUpdated\"\t\t\"${System.currentTimeMillis() / 1000}\"")
-                    appendLine("\t\"SizeOnDisk\"\t\t\"$sizeOnDisk\"")
-                    appendLine("\t\"buildid\"\t\t\"$buildId\"")
 
                     val actualInstallDir = gameName
                     appendLine("\t\"installdir\"\t\t\"${escapeString(actualInstallDir)}\"")
 
+                    appendLine("\t\"LastUpdated\"\t\t\"${System.currentTimeMillis() / 1000}\"")
+                    appendLine("\t\"LastPlayed\"\t\t\"0\"")
+                    appendLine("\t\"SizeOnDisk\"\t\t\"$sizeOnDisk\"")
+                    appendLine("\t\"StagingSize\"\t\t\"0\"")
+                    appendLine("\t\"buildid\"\t\t\"$buildId\"")
                     appendLine("\t\"LastOwner\"\t\t\"$ownerSteamId\"")
-                    appendLine("\t\"BytesToDownload\"\t\t\"0\"")
-                    appendLine("\t\"BytesDownloaded\"\t\t\"0\"")
+                    appendLine("\t\"DownloadType\"\t\t\"1\"")
+                    appendLine("\t\"UpdateResult\"\t\t\"0\"")
+                    appendLine("\t\"BytesToDownload\"\t\t\"$totalBytesToDownload\"")
+                    appendLine("\t\"BytesDownloaded\"\t\t\"$totalBytesToDownload\"")
+                    appendLine("\t\"BytesToStage\"\t\t\"$totalBytesToStage\"")
+                    appendLine("\t\"BytesStaged\"\t\t\"$totalBytesToStage\"")
+                    appendLine("\t\"TargetBuildID\"\t\t\"$buildId\"")
                     appendLine("\t\"AutoUpdateBehavior\"\t\t\"0\"")
                     appendLine("\t\"AllowOtherDownloadsWhileRunning\"\t\t\"0\"")
                     appendLine("\t\"ScheduledAutoUpdate\"\t\t\"0\"")
@@ -922,6 +985,12 @@ object SteamUtils {
                             appendLine("\t\t{")
                             appendLine("\t\t\t\"manifest\"\t\t\"${manifest.gid}\"")
                             appendLine("\t\t\t\"size\"\t\t\"${manifest.size}\"")
+                            val dlcAppId = allKnownDepots[depotId]?.dlcAppId
+                            if (dlcAppId != null && dlcAppId != SteamService.INVALID_APP_ID) {
+                                appendLine("\t\t\t\"dlcappid\"\t\t\"$dlcAppId\"")
+                            } else if (depotId in installedDlcAppIds) {
+                                appendLine("\t\t\t\"dlcappid\"\t\t\"$depotId\"")
+                            }
                             appendLine("\t\t}")
                         }
                         appendLine("\t}")
@@ -932,8 +1001,32 @@ object SteamUtils {
                         )
                     }
 
-                    appendLine("\t\"UserConfig\" { \"language\" \"english\" }")
-                    appendLine("\t\"MountedConfig\" { \"language\" \"english\" }")
+                    if (installScripts.isNotEmpty()) {
+                        appendLine("\t\"InstallScripts\"")
+                        appendLine("\t{")
+                        installScripts.forEach { (depotId, script) ->
+                            appendLine("\t\t\"$depotId\"\t\t\"${escapeString(script)}\"")
+                        }
+                        appendLine("\t}")
+                    }
+
+                    if (sharedDepots.isNotEmpty()) {
+                        appendLine("\t\"SharedDepots\"")
+                        appendLine("\t{")
+                        sharedDepots.forEach { (depotId, appTarget) ->
+                            appendLine("\t\t\"$depotId\"\t\t\"$appTarget\"")
+                        }
+                        appendLine("\t}")
+                    }
+
+                    appendLine("\t\"UserConfig\"")
+                    appendLine("\t{")
+                    appendLine("\t\t\"language\"\t\t\"$language\"")
+                    appendLine("\t}")
+                    appendLine("\t\"MountedConfig\"")
+                    appendLine("\t{")
+                    appendLine("\t\t\"language\"\t\t\"$language\"")
+                    appendLine("\t}")
                     appendLine("}")
                 }
 
@@ -948,13 +1041,43 @@ object SteamUtils {
                         appendLine("\"AppState\"")
                         appendLine("{")
                         appendLine("\t\"appid\"\t\t\"228980\"")
-                        appendLine("\t\"Universe\"\t\t\"1\"")
+                        appendLine("\t\"universe\"\t\t\"1\"")
+                        appendLine("\t\"LauncherPath\"\t\t\"C:\\\\Program Files (x86)\\\\Steam\\\\steam.exe\"")
                         appendLine("\t\"name\"\t\t\"Steamworks Common Redistributables\"")
                         appendLine("\t\"StateFlags\"\t\t\"4\"")
                         appendLine("\t\"installdir\"\t\t\"Steamworks Shared\"")
+                        appendLine("\t\"LastUpdated\"\t\t\"${System.currentTimeMillis() / 1000}\"")
+                        appendLine("\t\"LastPlayed\"\t\t\"0\"")
+                        appendLine("\t\"SizeOnDisk\"\t\t\"0\"")
+                        appendLine("\t\"StagingSize\"\t\t\"0\"")
                         appendLine("\t\"buildid\"\t\t\"1\"")
+                        appendLine("\t\"LastOwner\"\t\t\"0\"")
+                        appendLine("\t\"DownloadType\"\t\t\"1\"")
+                        appendLine("\t\"UpdateResult\"\t\t\"0\"")
                         appendLine("\t\"BytesToDownload\"\t\t\"0\"")
                         appendLine("\t\"BytesDownloaded\"\t\t\"0\"")
+                        appendLine("\t\"BytesToStage\"\t\t\"0\"")
+                        appendLine("\t\"BytesStaged\"\t\t\"0\"")
+                        appendLine("\t\"TargetBuildID\"\t\t\"1\"")
+                        appendLine("\t\"AutoUpdateBehavior\"\t\t\"0\"")
+                        appendLine("\t\"AllowOtherDownloadsWhileRunning\"\t\t\"0\"")
+                        appendLine("\t\"ScheduledAutoUpdate\"\t\t\"0\"")
+                        appendLine("\t\"InstalledDepots\"")
+                        appendLine("\t{")
+                        appendLine("\t\t\"228980\"")
+                        appendLine("\t\t{")
+                        appendLine("\t\t\t\"manifest\"\t\t\"0\"")
+                        appendLine("\t\t\t\"size\"\t\t\"0\"")
+                        appendLine("\t\t}")
+                        appendLine("\t}")
+                        appendLine("\t\"UserConfig\"")
+                        appendLine("\t{")
+                        appendLine("\t\t\"language\"\t\t\"english\"")
+                        appendLine("\t}")
+                        appendLine("\t\"MountedConfig\"")
+                        appendLine("\t{")
+                        appendLine("\t\t\"language\"\t\t\"english\"")
+                        appendLine("\t}")
                         appendLine("}")
                     }
 
@@ -1059,7 +1182,7 @@ object SteamUtils {
 
     private fun escapeString(input: String?): String {
         if (input == null) return ""
-        return input.replace("\"", "\\\"").replace("\n", "\\n").replace("\r", "\\r")
+        return input.replace("\\", "\\\\").replace("\"", "\\\"").replace("\n", "\\n").replace("\r", "\\r")
     }
 
     private fun calculateDirectorySize(directory: File): Long {
@@ -1482,8 +1605,8 @@ object SteamUtils {
                     container
                         .getExtra("containerLanguage", null)
                         ?.takeIf { it.isNotEmpty() }
-                        ?: "english"
-                }.getOrDefault("english")
+                        ?: PrefManager.containerLanguage
+                }.getOrDefault(PrefManager.containerLanguage)
 
             val steamappsDir = File(steamPath, "steamapps")
             val appManifestFile = File(steamappsDir, "appmanifest_$appId.acf")
diff --git a/app/src/main/res/values-da/strings.xml b/app/src/main/res/values-da/strings.xml
index 4f146e6a8..0ff272bb8 100644
--- a/app/src/main/res/values-da/strings.xml
+++ b/app/src/main/res/values-da/strings.xml
@@ -824,6 +824,8 @@ F.eks. <b>META</b> for <i>META-tast</i>, \n
 
     <string name="settings_other_language_title">Sprog</string>
     <string name="settings_other_language_summary">Vælg visningssprog</string>
+    <string name="settings_other_game_language_title">Spilsprog</string>
+    <string name="settings_other_game_language_summary">Foretrukket sprog til Steam/Epic/GOG-downloads</string>
     <string name="settings_other_language_system_default">Systemstandard</string>
 
     <string name="settings_other_section_integration">Integration</string>
diff --git a/app/src/main/res/values-de/strings.xml b/app/src/main/res/values-de/strings.xml
index 3db58b93d..54ffb32d7 100644
--- a/app/src/main/res/values-de/strings.xml
+++ b/app/src/main/res/values-de/strings.xml
@@ -824,6 +824,8 @@ Z. B. <b>META</b> für <i>Meta-Taste</i>, \n
 
     <string name="settings_other_language_title">Sprache</string>
     <string name="settings_other_language_summary">Anzeigesprache auswählen</string>
+    <string name="settings_other_game_language_title">Spielsprache</string>
+    <string name="settings_other_game_language_summary">Bevorzugte Sprache für Steam-/Epic-/GOG-Downloads</string>
     <string name="settings_other_language_system_default">Systemstandard</string>
 
     <string name="settings_other_section_integration">Integration</string>
diff --git a/app/src/main/res/values-es/strings.xml b/app/src/main/res/values-es/strings.xml
index f173826f6..b3d41d0aa 100644
--- a/app/src/main/res/values-es/strings.xml
+++ b/app/src/main/res/values-es/strings.xml
@@ -824,6 +824,8 @@ Ej. <b>META</b> para la <i>tecla META</i>, \n
 
     <string name="settings_other_language_title">Idioma</string>
     <string name="settings_other_language_summary">Elige el idioma de visualización</string>
+    <string name="settings_other_game_language_title">Idioma del juego</string>
+    <string name="settings_other_game_language_summary">Idioma preferido para las descargas de Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Predeterminado del sistema</string>
 
     <string name="settings_other_section_integration">Integración</string>
diff --git a/app/src/main/res/values-fr/strings.xml b/app/src/main/res/values-fr/strings.xml
index 15d7a9801..bdaa34f88 100644
--- a/app/src/main/res/values-fr/strings.xml
+++ b/app/src/main/res/values-fr/strings.xml
@@ -824,6 +824,8 @@ Par ex. <b>META</b> pour la <i>touche META</i>, \n
 
     <string name="settings_other_language_title">Langue</string>
     <string name="settings_other_language_summary">Choisir la langue d\'affichage</string>
+    <string name="settings_other_game_language_title">Langue du jeu</string>
+    <string name="settings_other_game_language_summary">Langue préférée pour les téléchargements Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Paramètre système</string>
 
     <string name="settings_other_section_integration">Intégration</string>
diff --git a/app/src/main/res/values-hi/strings.xml b/app/src/main/res/values-hi/strings.xml
index 73340af82..8c7f2d1c3 100644
--- a/app/src/main/res/values-hi/strings.xml
+++ b/app/src/main/res/values-hi/strings.xml
@@ -930,6 +930,8 @@
     <string name="settings_debug_remove_channel_desc">%1$s हटाएं</string>
     <string name="settings_other_language_title">भाषा</string>
     <string name="settings_other_language_summary">प्रदर्शन भाषा चुनें</string>
+    <string name="settings_other_game_language_title">गेम भाषा</string>
+    <string name="settings_other_game_language_summary">Steam/Epic/GOG डाउनलोड के लिए पसंदीदा भाषा</string>
     <string name="settings_other_language_system_default">सिस्टम डिफ़ॉल्ट</string>
     <string name="settings_other_section_integration">इंटीग्रेशन</string>
     <string name="settings_other_setup_wizard_title">सेटअप विज़ार्ड</string>
diff --git a/app/src/main/res/values-it/strings.xml b/app/src/main/res/values-it/strings.xml
index 8ce77f6ba..8f93d1b03 100644
--- a/app/src/main/res/values-it/strings.xml
+++ b/app/src/main/res/values-it/strings.xml
@@ -824,6 +824,8 @@ Ad es. <b>META</b> per il <i>tasto META</i>, \n
 
     <string name="settings_other_language_title">Lingua</string>
     <string name="settings_other_language_summary">Scegli la lingua di visualizzazione</string>
+    <string name="settings_other_game_language_title">Lingua del gioco</string>
+    <string name="settings_other_game_language_summary">Lingua preferita per i download di Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Predefinita di sistema</string>
 
     <string name="settings_other_section_integration">Integrazione</string>
diff --git a/app/src/main/res/values-ko/strings.xml b/app/src/main/res/values-ko/strings.xml
index d3e12a025..78cc5a1c3 100644
--- a/app/src/main/res/values-ko/strings.xml
+++ b/app/src/main/res/values-ko/strings.xml
@@ -824,6 +824,8 @@
 
     <string name="settings_other_language_title">언어</string>
     <string name="settings_other_language_summary">표시 언어 선택</string>
+    <string name="settings_other_game_language_title">게임 언어</string>
+    <string name="settings_other_game_language_summary">Steam/Epic/GOG 다운로드에 사용할 기본 언어</string>
     <string name="settings_other_language_system_default">시스템 기본값</string>
 
     <string name="settings_other_section_integration">통합</string>
diff --git a/app/src/main/res/values-pl/strings.xml b/app/src/main/res/values-pl/strings.xml
index 98613951f..9029fb2fd 100644
--- a/app/src/main/res/values-pl/strings.xml
+++ b/app/src/main/res/values-pl/strings.xml
@@ -830,6 +830,8 @@ Np. <b>META</b> dla <i>klawisza META</i>, \n
 
     <string name="settings_other_language_title">Język</string>
     <string name="settings_other_language_summary">Wybierz język wyświetlania</string>
+    <string name="settings_other_game_language_title">Język gry</string>
+    <string name="settings_other_game_language_summary">Preferowany język pobierania ze Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Domyślny systemu</string>
 
     <string name="settings_other_section_integration">Integracja</string>
diff --git a/app/src/main/res/values-pt-rBR/strings.xml b/app/src/main/res/values-pt-rBR/strings.xml
index 7bd36eee2..a0a63ae69 100644
--- a/app/src/main/res/values-pt-rBR/strings.xml
+++ b/app/src/main/res/values-pt-rBR/strings.xml
@@ -824,6 +824,8 @@ Ex. <b>META</b> para <i>tecla META</i>, \n
 
     <string name="settings_other_language_title">Idioma</string>
     <string name="settings_other_language_summary">Escolher o idioma de exibição</string>
+    <string name="settings_other_game_language_title">Idioma do jogo</string>
+    <string name="settings_other_game_language_summary">Idioma preferido para downloads da Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Padrão do sistema</string>
 
     <string name="settings_other_section_integration">Integração</string>
diff --git a/app/src/main/res/values-ro/strings.xml b/app/src/main/res/values-ro/strings.xml
index 8411c5bc1..ba83b3740 100644
--- a/app/src/main/res/values-ro/strings.xml
+++ b/app/src/main/res/values-ro/strings.xml
@@ -824,6 +824,8 @@ De ex. <b>META</b> pentru <i>tasta META</i>, \n
 
     <string name="settings_other_language_title">Limbă</string>
     <string name="settings_other_language_summary">Alege limba de afișare</string>
+    <string name="settings_other_game_language_title">Limba jocului</string>
+    <string name="settings_other_game_language_summary">Limba preferată pentru descărcările Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Implicit sistem</string>
 
     <string name="settings_other_section_integration">Integrare</string>
diff --git a/app/src/main/res/values-ru/strings.xml b/app/src/main/res/values-ru/strings.xml
index 392f3549a..234250637 100644
--- a/app/src/main/res/values-ru/strings.xml
+++ b/app/src/main/res/values-ru/strings.xml
@@ -891,6 +891,8 @@
     <string name="settings_debug_remove_channel_desc">Удалить %1$s</string>
     <string name="settings_other_language_title">Язык</string>
     <string name="settings_other_language_summary">Выберите язык интерфейса</string>
+    <string name="settings_other_game_language_title">Язык игры</string>
+    <string name="settings_other_game_language_summary">Предпочитаемый язык для загрузок Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">Системный язык</string>
     <string name="settings_other_section_integration">Интеграция</string>
     <string name="settings_other_setup_wizard_title">Мастер установки</string>
diff --git a/app/src/main/res/values-uk/strings.xml b/app/src/main/res/values-uk/strings.xml
index 45c92c010..89f732be6 100644
--- a/app/src/main/res/values-uk/strings.xml
+++ b/app/src/main/res/values-uk/strings.xml
@@ -830,6 +830,8 @@
 
     <string name="settings_other_language_title">Мова</string>
     <string name="settings_other_language_summary">Виберіть мову інтерфейсу</string>
+    <string name="settings_other_game_language_title">Мова гри</string>
+    <string name="settings_other_game_language_summary">Бажана мова для завантажень Steam/Epic/GOG</string>
     <string name="settings_other_language_system_default">За замовчуванням системи</string>
 
     <string name="settings_other_section_integration">Інтеграція</string>
diff --git a/app/src/main/res/values-zh-rCN/strings.xml b/app/src/main/res/values-zh-rCN/strings.xml
index 20e4aec3e..8ca809864 100644
--- a/app/src/main/res/values-zh-rCN/strings.xml
+++ b/app/src/main/res/values-zh-rCN/strings.xml
@@ -824,6 +824,8 @@
 
     <string name="settings_other_language_title">语言</string>
     <string name="settings_other_language_summary">选择显示语言</string>
+    <string name="settings_other_game_language_title">游戏语言</string>
+    <string name="settings_other_game_language_summary">Steam/Epic/GOG 下载的首选语言</string>
     <string name="settings_other_language_system_default">系统默认</string>
 
     <string name="settings_other_section_integration">集成</string>
diff --git a/app/src/main/res/values-zh-rTW/strings.xml b/app/src/main/res/values-zh-rTW/strings.xml
index 90001b4e8..e02d28820 100644
--- a/app/src/main/res/values-zh-rTW/strings.xml
+++ b/app/src/main/res/values-zh-rTW/strings.xml
@@ -824,6 +824,8 @@
 
     <string name="settings_other_language_title">語言</string>
     <string name="settings_other_language_summary">選擇顯示語言</string>
+    <string name="settings_other_game_language_title">遊戲語言</string>
+    <string name="settings_other_game_language_summary">Steam/Epic/GOG 下載的偏好語言</string>
     <string name="settings_other_language_system_default">系統預設</string>
 
     <string name="settings_other_section_integration">整合</string>
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index faae17665..45d60c5cd 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -1113,6 +1113,8 @@ E.g. <b>META</b> for <i>META key</i>, \n
     <string name="settings_other_language_title">Language</string>
     <string name="settings_other_language_summary">Choose the display language</string>
     <string name="settings_other_language_system_default">System default</string>
+    <string name="settings_other_game_language_title">Game Language</string>
+    <string name="settings_other_game_language_summary">Preferred language for Steam/Epic/GOG downloads</string>
 
     <string name="settings_other_section_integration">Integration</string>
     <string name="settings_other_setup_wizard_title">Setup Wizard</string>
diff --git a/app/src/main/runtime/display/XServerDisplayActivity.java b/app/src/main/runtime/display/XServerDisplayActivity.java
index 85a0ec55b..bab8847e7 100644
--- a/app/src/main/runtime/display/XServerDisplayActivity.java
+++ b/app/src/main/runtime/display/XServerDisplayActivity.java
@@ -5926,8 +5926,11 @@ private void setupSteamGameFiles() {
             int appId = Integer.parseInt(shortcut.getExtra("app_id"));
             String gameInstallPath = resolveSteamGameInstallPath(appId);
             File gameDir = new File(gameInstallPath);
-            String language = container.getExtra("containerLanguage", "english");
-            if (language == null || language.isEmpty()) language = "english";
+            String language = PrefManager.INSTANCE.getContainerLanguage();
+            String containerLang = container.getExtra("containerLanguage", null);
+            if (containerLang != null && !containerLang.isEmpty()) {
+                language = containerLang;
+            }
             boolean isOfflineMode = parseBoolean(
                     getShortcutSetting("steamOfflineMode",
                             container.isSteamOfflineMode() ? "1" : "0"));
@@ -6766,6 +6769,179 @@ private void setupXEnvironment() throws PackageManager.NameNotFoundException {
                         envVars.put("WN_STEAM_STEAMID", planWSid);
                         envVars.put("WN_STEAM_TOKEN", planWTok);
                         envVars.put("WN_STEAM_APPID", String.valueOf(bsAppId));
+                        // Pass language for native launcher ACF UserConfig/MountedConfig
+                        String acfLang = PrefManager.INSTANCE.getContainerLanguage();
+                        String acfContainerLang = container.getExtra("containerLanguage", null);
+                        if (acfContainerLang != null && !acfContainerLang.isEmpty()) {
+                            acfLang = acfContainerLang;
+                        }
+                        if (acfLang != null && !acfLang.isEmpty()) {
+                            envVars.put("WN_STEAM_LANGUAGE", acfLang);
+                        }
+                        // Pass DLC depot data for native launcher ACF
+                        try {
+                            com.winlator.cmod.feature.stores.steam.data.SteamApp depotAppInfo =
+                                com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                    .getAppInfoOf(bsAppId);
+                            if (depotAppInfo != null) {
+                                envVars.put("WN_STEAM_APP_NAME", depotAppInfo.getName());
+                                String installScript = depotAppInfo.getInstallScript();
+                                if (installScript != null && !installScript.isEmpty()) {
+                                    StringBuilder installScriptsSb = new StringBuilder();
+                                    java.util.Map<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> allDepots =
+                                        depotAppInfo.getDepots();
+                                    for (java.util.Map.Entry<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> entry : allDepots.entrySet()) {
+                                        com.winlator.cmod.feature.stores.steam.data.DepotInfo di = entry.getValue();
+                                        if (di.getDlcAppId() == com.winlator.cmod.feature.stores.steam.service.SteamService.INVALID_APP_ID
+                                            && di.getDepotFromApp() == com.winlator.cmod.feature.stores.steam.service.SteamService.INVALID_APP_ID) {
+                                            if (installScriptsSb.length() > 0) installScriptsSb.append(",");
+                                            installScriptsSb.append(entry.getKey()).append(":").append(installScript);
+                                        }
+                                    }
+                                    if (installScriptsSb.length() > 0) {
+                                        envVars.put("WN_STEAM_INSTALL_SCRIPTS", installScriptsSb.toString());
+                                    }
+                                }
+                                java.util.Map<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> depots =
+                                    depotAppInfo.getDepots();
+                                String branch = com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                    .resolveSelectedBetaName(bsAppId);
+                                if (branch == null || branch.isEmpty()) branch = "public";
+
+                                // Resolve buildId from branch info
+                                java.util.Map<String, com.winlator.cmod.feature.stores.steam.data.BranchInfo> branches =
+                                    depotAppInfo.getBranches();
+                                long buildId = 0L;
+                                if (branches != null) {
+                                    com.winlator.cmod.feature.stores.steam.data.BranchInfo branchInfo = branches.get(branch);
+                                    if (branchInfo != null) {
+                                        buildId = branchInfo.getBuildId();
+                                    } else if (branches.containsKey("public")) {
+                                        buildId = branches.get("public").getBuildId();
+                                    }
+                                }
+                                envVars.put("WN_STEAM_BUILD_ID", String.valueOf(buildId));
+
+                                // Compute sizeOnDisk recursively from game directory (match Kotlin
+                                // calculateDirectorySize); null-guard listFiles() so a transient I/O
+                                // error never NPEs and silently drops all depot data.
+                                String gameInstallPath = resolveSteamGameInstallPath(bsAppId);
+                                long sizeOnDisk = 0L;
+                                if (gameInstallPath != null) {
+                                    java.util.ArrayDeque<java.io.File> stack = new java.util.ArrayDeque<>();
+                                    stack.push(new java.io.File(gameInstallPath));
+                                    while (!stack.isEmpty()) {
+                                        java.io.File cur = stack.pop();
+                                        if (cur.isDirectory()) {
+                                            java.io.File[] children = cur.listFiles();
+                                            if (children != null) {
+                                                for (java.io.File c : children) stack.push(c);
+                                            }
+                                        } else if (cur.isFile()) {
+                                            sizeOnDisk += cur.length();
+                                        }
+                                    }
+                                }
+                                envVars.put("WN_STEAM_SIZE_ON_DISK", String.valueOf(sizeOnDisk));
+
+                                // Collect installed depot IDs and DLC app IDs (same as Kotlin collectInstalledDepotManifests)
+                                java.util.Set<Integer> installedDepotIds = new java.util.HashSet<>();
+                                java.util.List<Integer> installedDepotsList = com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                    .getInstalledDepotsOf(bsAppId);
+                                if (installedDepotsList != null) installedDepotIds.addAll(installedDepotsList);
+
+                                java.util.Set<Integer> installedDlcAppIds = new java.util.HashSet<>();
+                                java.util.List<Integer> installedDlcList = com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                    .getInstalledDlcDepotsOf(bsAppId);
+                                if (installedDlcList != null) installedDlcAppIds.addAll(installedDlcList);
+
+                                // Collect all known depots (app depots + downloadable depots)
+                                java.util.LinkedHashMap<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> allKnownDepots = new java.util.LinkedHashMap<>();
+                                allKnownDepots.putAll(depots);
+                                java.util.Map<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> downloadableDepots = com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                    .getDownloadableDepots(bsAppId, acfLang != null ? acfLang : "");
+                                if (downloadableDepots != null) allKnownDepots.putAll(downloadableDepots);
+
+                                // Also add DLC depots from getOwnedAppDlc (matches Kotlin collectInstalledDepotManifests)
+                                if (installedDlcList != null) {
+                                    for (Integer dlcAppId : installedDlcList) {
+                                        try {
+                                            @SuppressWarnings("unchecked")
+                                            java.util.Map<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> ownedDlc =
+                                                (java.util.Map<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo>)
+                                                    kotlinx.coroutines.BuildersKt.runBlocking(
+                                                        kotlinx.coroutines.Dispatchers.getIO(),
+                                                        (scope, continuation) -> com.winlator.cmod.feature.stores.steam.service.SteamService.Companion
+                                                            .getOwnedAppDlc(dlcAppId, continuation)
+                                                    );
+                                            if (ownedDlc != null) allKnownDepots.putAll(ownedDlc);
+                                        } catch (InterruptedException ie) {
+                                            Thread.currentThread().interrupt();
+                                        } catch (Exception ignored) {}
+                                    }
+                                }
+
+                                StringBuilder depotSb = new StringBuilder();
+                                StringBuilder sharedSb = new StringBuilder();
+                                long totalBytesToDownload = 0L;
+                                long totalBytesToStage = 0L;
+                                for (java.util.Map.Entry<Integer, com.winlator.cmod.feature.stores.steam.data.DepotInfo> entry : allKnownDepots.entrySet()) {
+                                    int depotId = entry.getKey();
+                                    com.winlator.cmod.feature.stores.steam.data.DepotInfo di = entry.getValue();
+
+                                    // Shared depots are excluded from InstalledDepots entirely (match Kotlin
+                                    // collectInstalledDepotManifests); emit to SharedDepots only when the source app is known.
+                                    if (di.getSharedInstall()) {
+                                        if (di.getDepotFromApp() != com.winlator.cmod.feature.stores.steam.service.SteamService.INVALID_APP_ID) {
+                                            if (sharedSb.length() > 0) sharedSb.append(",");
+                                            sharedSb.append(depotId).append(":").append(di.getDepotFromApp());
+                                        }
+                                        continue;
+                                    }
+
+                                    // Match Kotlin collectInstalledDepotManifests: include if depot is installed,
+                                    // or its DLC is installed
+                                    boolean shouldInclude = installedDepotIds.contains(depotId)
+                                        || (di.getDlcAppId() != com.winlator.cmod.feature.stores.steam.service.SteamService.INVALID_APP_ID
+                                            && installedDlcAppIds.contains(di.getDlcAppId()));
+                                    if (!shouldInclude) continue;
+
+                                    com.winlator.cmod.feature.stores.steam.data.ManifestInfo manifest = null;
+                                    java.util.Map<String, com.winlator.cmod.feature.stores.steam.data.ManifestInfo> manifests = di.getManifests();
+                                    if (manifests.containsKey(branch)) manifest = manifests.get(branch);
+                                    else if (!branch.equals("public") && manifests.containsKey("public")) manifest = manifests.get("public");
+                                    if (manifest != null && manifest.getGid() != 0L) {
+                                        if (depotSb.length() > 0) depotSb.append(",");
+                                        depotSb.append(depotId).append(":").append(manifest.getGid()).append(":").append(manifest.getSize());
+                                        int dlcAppId = di.getDlcAppId();
+                                        if (dlcAppId != com.winlator.cmod.feature.stores.steam.service.SteamService.INVALID_APP_ID) {
+                                            depotSb.append(":").append(dlcAppId);
+                                        } else if (installedDlcAppIds.contains(depotId)) {
+                                            // Mirror Kotlin createAppManifest: fall back to depotId as the dlcappid
+                                            // when the depot carries no dlcAppId but is itself a tracked DLC.
+                                            depotSb.append(":").append(depotId);
+                                        }
+                                        totalBytesToDownload += manifest.getDownload();
+                                        totalBytesToStage += manifest.getSize();
+                                    }
+                                }
+                                if (depotSb.length() > 0) {
+                                    envVars.put("WN_STEAM_DEPOTS", depotSb.toString());
+                                }
+                                if (sharedSb.length() > 0) {
+                                    envVars.put("WN_STEAM_SHARED_DEPOTS", sharedSb.toString());
+                                }
+                                envVars.put("WN_STEAM_BYTES_TO_DOWNLOAD", String.valueOf(totalBytesToDownload));
+                                envVars.put("WN_STEAM_BYTES_TO_STAGE", String.valueOf(totalBytesToStage));
+                                Log.i("XServerDisplayActivity",
+                                    "Steam Launcher: depots=" + depotSb + " shared=" + sharedSb
+                                    + " buildId=" + buildId + " sizeOnDisk=" + sizeOnDisk
+                                    + " dlBytes=" + totalBytesToDownload + " stageBytes=" + totalBytesToStage);
+                            }
+                        } catch (Exception depotIgnored) {
+                            Log.w("XServerDisplayActivity",
+                                    "Steam Launcher: Could not query depot data", depotIgnored);
+                        }
                         if (wnSteamDirectExeOverride) {
                             envVars.put("WN_STEAM_DIRECT_EXE", "1");
                             Log.i("XServerDisplayActivity",
@@ -10394,11 +10570,20 @@ private void setupSteamEnvironment(int appId, File gameDir) {
             commonDir.mkdirs();
             WineUtils.ensureSteamappsCommonSymlink(container, gameDir.getAbsolutePath());
 
-            SteamUtils.createAppManifest(this, appId);
+            String acfLanguage = PrefManager.INSTANCE.getContainerLanguage();
+            String containerLang = container.getExtra("containerLanguage", null);
+            if (containerLang != null && !containerLang.isEmpty()) {
+                acfLanguage = containerLang;
+            }
+            SteamUtils.createAppManifest(this, appId, acfLanguage);
 
             File defaultAcf = new File(imageFs.getRootDir(),
                     ImageFs.WINEPREFIX + "/drive_c/Program Files (x86)/Steam/steamapps/appmanifest_" + appId + ".acf");
             File containerAcf = new File(steamappsDir, "appmanifest_" + appId + ".acf");
+            // Refresh the container manifest from the freshly generated one on every launch so
+            // newly installed DLC / language changes propagate. The generated manifest is the
+            // source of truth (the native launcher rewrites this same file too), so a stale
+            // container copy must not be left in place.
             if (defaultAcf.exists()) {
                 try {
                     java.nio.file.Files.copy(defaultAcf.toPath(), containerAcf.toPath(),
@@ -10416,7 +10601,7 @@ private void setupSteamEnvironment(int appId, File gameDir) {
                 String steamworksAcfContent = "\"AppState\"\n" +
                         "{\n" +
                         "\t\"appid\"\t\t\"228980\"\n" +
-                        "\t\"Universe\"\t\t\"1\"\n" +
+                        "\t\"universe\"\t\t\"1\"\n" +
                         "\t\"name\"\t\t\"Steamworks Common Redistributables\"\n" +
                         "\t\"StateFlags\"\t\t\"4\"\n" +
                         "\t\"installdir\"\t\t\"Steamworks Shared\"\n" +