

Works well out of the box

Installs fine, works with some tinkering.
PROTON_USE_WINED3D=1 PROTON_NO_ESYNC=1 PROTON_NO_FSYNC=1 %command%
I had to change the settings.ini file to force the screen in windowed mode. In fact, the contents are as follows:
[Game]
volume=1
sensitivity=2
mouse_invert=0
resolution_x=1440
resolution_y=900
fullscreen=0
vsync=0
cap = 144
fov=65
//volume 0.0-1.0
//sensitivity 0.0-??
//mouse_invert 0=no inversion, 1=inverted
//resolution_x,resolution_y -1=maximum allowed resolution
//fullscreen 0=windowed, 1=fullscreen, 2=borderless
//vsync 0=off, 1=on
//cap 0-?? framerate cap (only if vsync is off)
//fov 0-?? vertical fov
Reading the reports on ProtonDB, I expected the game to work immediately. This was not the case. I had to force the game in windowed mode (or else some weird rendering issues occur) by editing the settings.ini file.
runs without issues

No issues encountered

Didn't change anything at all and the game played beautifully. There's a console in the submarine that can be accessed only through typing, but its contents are completely optional and the overlay keyboard works perfectly well anyway.
The game works exceptionally without any modifications.
Runs fantastic, just like a native application.
The in-game console works flawlessly with the Steam keyboard activated

It ran very well and everything worked almost if not just perfectly.
There were some random grey pixels to the right of my screen with higher FOV settings, but they did not cause any gameplay problems.
The game would freak out upon tabbing out unless I had the map up, causing it to teleport my mouse to other montiors, or freeze completely, this may be a result of me still having Sloppy Focus. (Sloppy Focus is when windows gain focus upon the mouse moving over them)
Other than the windowing issue it plays perfectly fine, I was able to get all achievements without loosing too much progress from the 2 or so times it happened.
The windowing issue is avoidable if I only tab out with the map open and never with the exit game prompt open.
The game weighs ~200MiB in total so there's not much that actually can break
Game works perfectly if the specified command line settings are set. Otherwise the game does not launch.
PROTON_USE_WINED3D11=1 %command%
You need to set the command line parameters to PROTON_USE_WINED3D11=1 %command%
, otherwise the game does not start. I suspect this fix is only necessary for iGPU users.
Works without issues out of the box
Amazing game, great story, and ran out of the box without even changing the proton version.
Game is very scary but linux is not afraid of it.
Game worked perfectly
Game ran completely out of the box with the default version of proton with no issues throughout the entire play through