Oneshot is a challenging game because it relies on external components for its gameplay mechanics like changing the wallpaper or moving the window. Things which don’t work anymore on the Linux version due to how things have changed in Linux. Proton does work well, the window moving stuff works but wallpaper changing doesn’t work.

Other older Linux games can usually be played using older Steam Linux Runtime without much issue. Oneshot is a niche and special case.

The developer also released OneShot WME which uses a fake Desktop to accomplish the mechanics without relying on the actual desktop or Window manager. That one can be played in Steam Big picture.

The OG OneShot Linux port is known to be extremely broken since it was really poorly developed. Even after applying a fix to get it to boot, it relies on old standards to do things like changing your wallpaper, so those features often won’t work.

I’d highly suggest getting OneShot Wold Machine Edition which a remake/remaster of the original which takes place in a fake PC with a fake desktop that allows all those features to work in an isolated environment. Doesn’t have a native Linux version, but the dev explicitly tested on Proton to make sure everything worked properly(specifically for the Steam Deck, but same difference).

@forestbeasts There’s also the Legacy Runtime, that’s still native to Linux. I have to do that for some things instead of the ‘Scout’ or normal one.