Proton is only mentioned if it's required despite there being a native version of the game.
UPDATE : SteamVR for Linux has been horrendously broken for a while on Linux, at least for me. Asynchronous reprojection is a mess, additional trackers don't show up, and there's still no Wayland support. This appears to be mostly NVidia's fault.
So, you know, as usual, don't buy NVidia cards.
Error -203 sometimes. Seems random?
Very sensitive to antialiasing settings.
You need to run the game in Proton because the VR version uses DirectX to work.
Don't press the function keys.
You don't even need the Windows version running in Proton to use mods. Mono just kinda works with Windows DLLs. C# is fucking wack yo.
Install the platform spoofing mod if you need to use Proton.
Otherwise, completely playable.
You need to force it to run in Proton. Go to its properties and set the compatibility tool to any given Proton version.
Error -203 shortly after loading into a mission. Usually, right when the game says "Stealth is also an option" so presumably level data is being initialized then, or something?
The garbage custom audio codec they licensed doesn't fucking work on Linux regardless of what I do.
...and that's like half the game so it's basically unplayable.