To preface: my hardware does not support Vulkan and thus any solution involving DXVK will not work. But this game is DirectX 9, so all should be fine, except it's not. I've worked at this for hours trying to find a way to get Proton to play nice and I believe I've narrowed the issue down to a 64-bit vs 32-bit problem.

This game will run manually with with WINEARCH=win32 wine wineboot && winetricks d3dx9 and then cd ~./local/share/Steam/steamapps/common/Dungeon\ Warfare\ 2 && wine DungeonWarfare2.exe` but it will decidedly stop you from playing because it was not launched via Steam. The only way to play, then, is to install Steam via Winetricks, but that is outside the scope of Proton.

Curiously, when running via Proton, the game complains, "Make sure you have DirectX 11 installed." I'm uncertain why this is, but I believe it to be related to the 64-bit profile that Proton creates. I've tried enforcing 32-bit profiles through Proton but, after much headache, I've so far been unsuccessful. I'm not sure why DX11 is brought up... can anyone confirm that this game possibly has a DX11 mode if a 64-bit environment is detected? I struggle to find any other explanation for why there are so many Platinums from cards that support Vulkan and I get DX11 errors that allude to DXVK being invoked on a system for which it is not allowed. If this is accurate, then the developers need to clarify on their system requirements. But it could be some quirky behavior of Proton I've yet to understand.

This game is well within my specifications; for now, I must give it a Borked.