

Some flickering in some areas, but this may not be Proton related, since the game is known to have graphical issues on Windows too.
Game only runs in 720p. Does not support 800p.
The game will inexplicably fall to ~40-50fps when entering some areas or when some graphical effects occur, despite having plenty of CPU/GPU headroom. However this is very infrequent and only happened a couple of times in the whole game.
It's a poor PC port, but for the most part plays well.

Drops to low 50/high 40 FPS during heavier moments, despite having plenty of CPU/GPU headroom

OK

Only played a few minutes as I did not have my controller nearby. Used keyboard to navigate. But all seemed to work ok, no tweaking or modifying needed.

Screen goes black for a second then the game immediately closes.

Crashes an boot if not started with bootoptions "PROTON_USE_WINED3D=1 %command%".
Works fine then.