


DXVK_FRAME_RATE=120 %command%
As you'd expect, this is about as flawless as it gets. It runs out of the box with zero issues. My laptop has a 300Hz screen, and the game automatically enables Vsync without a framerate cap ability, so I just capped it at 120fps with DXVK_FRAME_RATE=120
.

TDP to 8W
Played the whole game on the Deck. TDP to 8W to save battery but could put 40fps and lower W to improve duration. There are some times when the game asks you for a name. The Deck's keyboard appears correctly but if you want to check a persons name in-game the pop up window is kept open, so you need to close it after going to a persons file. Annoying but very minor. I recommend playing it on the Deck, great experience!

proton 8.0-5 & xbox360controller
works well

At some point during one of the introduction scenes audio crackled for a very short couple of seconds, but other than that I've experienced no problems whatsoever. Standard control scheme is probably not the most comfy, but there's plenty alternatives in the community custom profiles.
40FPS
Works out of the box.

Screen rate to 40 since it's a visual novel. Limiting TDP does decrease performance, so left it on default.
Game freezes sometimes, it won't let you input anything, even if the music is still playing in the background. You have to restart the game to continue. It happened like every two or three hours.
In my ~14 hours of playing, the game stalled twice (music still played and characters blinked, but no matter if I pressed the A button or tapped the screen I could not proceed) and refused to take inputs three times (when presented with a choice, despite pressing A or tapping the screen it would not register that anything was happening. To solve both of these problems I had to turn the game back off and then turn it back on. I don't know if this is because I was playing via Proton or a fault of the game itself but I figure this is worth mentioning.

Keyboard had to be opened manually, but everything else works perfectly.

I didn't test other Proton's versions.
Additional info:
Game seems to have problem with screen tearing (either on Linux or Windows), but setting GLSyncToVblank
to true
resolved this issue.
The game runs almost perfectly on the steam deck. The only issue I found it showing sometimes the loading icon when there is nothing to load, and that blocks the menu. But you can still continue the game anyway.
Everything default. So far I did have to bring up the keyboard to enter my name, but that's it so far. Controls work fine.
Trying to launch the game using any GloriousEggroll version of Proton results in an instant crash. However after switching to Proton Experimental there hasn't been any issues after an hour of playtime. Other regular versions of Proton hasn't been tested. If performance from the experimental version changes later during my playthrough this report will be updated - but this far there haven't been any issues.