Had the "DirectX 12 is not supported" error despite trying everything (Proton verisons, Graphics Driver update, and other launch option flags like -dx12) The following command allowed the game to launch and it works well after a 4 hour session. VKD3D_SHADER_MODEL=6_6 %command% I found that command here: https://github.com/ValveSoftware/Proton/issues/6949 Only had 1 random crash on the graphics option menu. (before i changed to windowed mode) Online coop works fine with 1 other person. The only complaint is that the performance is choppy at certain areas or fights.