Playing on the Steam Deck

The Steam Deck is known for being able to seamlessly run Windows software through Proton, the Wine wrapper. Running Oni on the Deck is thus easier than directly using Wine to run Oni in Linux. While Oni should work out of the box, you will likely experience dropped frames when sounds play, especially rapid-fire sounds like gunfire. Follow these steps to solve the issue.

1. Switch from SteamOS to the Linux desktop by choosing Steam Menu > Power > Switch to Desktop.
2. Install Oni (vanilla or Anniversary Edition) on a Windows PC and transfer the files to the Deck using a flash drive.
3. Install the app "ProtonUp-Qt" from the Discover app (Software Center), which should be in the taskbar already.
4. Add the Oni installation's EXE (or the EXE in the AE folder if you copied over AE Oni) to Steam as a non-Steam game. You can quickly do this by right-clicking the app and choosing "Add to Steam".
5. Right-click Oni in Steam and choose Properties > Compatibility. Check the box "Force the use of a specific Steam Play compatibility tool" and choose the latest version of Proton. Oni is ready to run at this point, but sound effects will cause it to drop frames.
6. Download msacm32.dll and drop it into the Oni or AE directory.
7. Add WINEDLLOVERRIDES="msacm=n,b" %command% in the Steam launch options for the game.
8. Launch it! The first time you run Oni, Steam will have to download a Steam Linux runtime and the version of Proton which you selected, so sit tight.