Not a port: this is the Steam release of Sonic Adventure 2, modded with Adventure Mods and launched through Steam under Proton. Every byte of game data belongs to Steam.
¶ What this is
The Windows version from Steam, with SA Mod Manager installed in place of the original launcher. Setup renames Launcher.exe to a .bak and puts the mod manager there; sonic2app.exe is still the real game. The manager loads the 16-mod preset from mods/, then starts the game.
That is why it is documented on this page but rated as a commercial Windows release rather than a native port: nothing was recompiled, and the game only runs because Proton and DXVK do the translation.
¶ Requirements
- Ownership: Sonic Adventure 2 on Steam. No game files ship with the launcher.
- Proton 10.0 (Steam app 3658110) forced for this title. GE-Proton10-34 also works. SA Mod Manager does not start on Proton 11, Experimental or Hotfix builds.
- .NET Desktop 8 and 10 inside the game's Proton prefix.
- AdventureMods flatpak 1.2.2, used only for setup, updating and restoring.
¶ Launch
Always start it through Steam, so Proton uses the game's own prefix.
Launching sonic2app.exe directly skips both the per-game Proton choice and the prefix holding .NET, so the mod manager never appears.
¶ Linux specifics: Direct3D 8 on Vulkan
SA2 is a Direct3D 8 game, and Proton only forces DXVK for d3d9, d3d11 and dxgi. Left alone, d3d8 falls back to WineD3D.
The fix is deliberate: d3d8.dll, d3d9.dll and dxgi.dll copied from Proton's DXVK i386 directory (not the Wine builtins) sit next to sonic2app.exe, and the prefix carries the override HKCU\Software\Wine\DllOverrides, d3d8 = native,builtin (plus d3d9 and dxgi). The result is D3D8 translated to Vulkan.
To fall back to WineD3D, delete the three DLLs and remove the d3d8 override. If rendering looks wrong, suspect the SA2 Render Fix mod against DXVK before anything else.
¶ Mods and saves
- Mods: managed by SA Mod Manager from
mods/in the game directory. - Saves: inside the Proton prefix (
compatdata/213610/.../users/steamuser), so they survive a mod restore. - Undo the mods:
flatpak run io.github.astrovm.AdventureMods restore.
¶ Where to get them
- Adventure Mods (astrovm/AdventureMods) installs this whole set on Linux. It finds the Steam install, downloads the mods, sets up SA Mod Manager, the .NET runtime, resolution and load order, and can undo everything with
flatpak run io.github.astrovm.AdventureMods restore.list-mods --game sa2shows the available mods and their slugs. - GameBanana hosts the individual mods under Sonic Adventure 2. That is where to look for a specific one, or for something outside the preset; install it through SA Mod Manager.
- SA Mod Manager is the manager Adventure Mods puts in place of
Launcher.exe. It is how mods are enabled, ordered and configured after setup.
¶ Known issues
- "No supported games detected": AdventureMods reads
steamapps/libraryfolders.vdfand needs the app id inside itsappsmap. Quit Steam once from its own UI so the file is rewritten;steam -shutdownover SSH does not reach the running client. - .NET installer fails with code 203: that is
0xCB, "Failed to create main window". It needs a display even when quiet, so exportDISPLAY=:0before setup. It is not a Proton version problem. - Setup seems frozen: the log writes in bursts. Judge progress by the
mods/folder growing and give it several minutes; killing it mid-write is how you get a half-installed set. - Mod manager on Proton 11+: it will not start. Stay on 10.
¶ Rating
🥈 Silver. A commercial Windows release rather than a port, held back by the Proton 10
ceiling and the setup traps, but with 16 mods and Vulkan rendering it works very well. Provisional.