I did experience two random crashes playing with default Proton. Maybe just a coincidence, but after switching to experimental did not experience any issues.

Vsync option in the game does not work, you can use launch option "DXVK_FRAME_RATE=60 %command%" to limit framerate.

Some scenes of the game can be demanding, so people playing on Steam Deck may need to turn down graphic settings. As with most Chillas Arts games, to access the graphic settings you have to start the game and then hit enter.