A minor "menu fullscreen window switch graphics glitch" where if you press on Enable Fullscreen or Disable Fullscreen there is a short pause where after pressing on either you can still see the choice you pressed on being displayed on the screen for 0.6-1 seconds until it switches to the one you chose. Same if using Proton Experimental, 7.0-3, 6.3-8 though more pronounced graphical glitches would occur when using Proton, so Linux native is better.

Using Proton 5.13-6, 5.0-10, 4.11-13 the game wouldn't even start.

Didn't try the 3 remaining ones: 4.2-9, 3.16-9 and 3.7-8 so if somebody feels motivated to test those versions, you can do that.