

You'll have to play around with your controller settings as mouse is required for menu navigation
Had to turn down all volume settings but dialogue as it would be too quiet with all volume modes at max
Game doesn't appear until after the intro cutscenes, which can be heard
Minor stuttering when game is streaming or loading new environments; can chug when a lot of explosions are happening
Plays surprisingly well for PS2/Xbox era game, minor issues probably due to the game itself, not Proton.
Campaign is playable from start to finish
Game window is invisible while the cinematic intro is playing
Random frame drops
Game does not launch (no visible window when I alt-tab) but loading screen & main menu audio can be heard.
Intro video does not work (either it hangs or fails to open a window.) If you can hear the audio, pressing Esc might skip it, but a sure and easy fix is to rename/delete the file movies/FULLIntroMovies.bik and the game goes straight to menu. (You can use mpv or whatever to watch it if you like.)
Without D9VK there are rendering bugs. People, and sometimes other objects too, are renderer completely black. (Before D9VK I managed to remedy the issue using dgVoodoo2 and DXVK, too.) Not sure if it is 100% even now but at least it is playable.

The game doesn't appear until it is done playing the 5 minute long intro video, you can hear the video but no game window will appear until it's done playing. Characters and enemies don't render properly, they are completely black unless performing certain actions. This is a small improvement over older version of Proton (3.7-8) where besides the characters props wouldn't render properly either showing as black or invisible.