Breaks if not using NVIDIA Driver Version 470, Proton 7.0-6. If Driver Version is changed, loads to campaign menu and allows you to select "New Game", but freezes during loading. If a new game is started using NVIDIA 470 and Proton 7.0-6, the game works with slight performance reductions compared to Windows.

If the driver version is changed after starting a new campaign using the configuration outlined above, the game proceeds to load, but freezes upon zooming in to the submarine after loading (The sub is visible, game freezes).

Other configurations seem to result in one of the two game-breaking issues.