

Works perfectly out of the box for the steam deck, controller prompts are hard-coded for keyboard, but gamepad works out of the box.
Fullscreen causes the game to only show the top left corner of the screen, since the game is default to window this is not a major problem.
The game doesn't seem to allow you to close out of it with a menu option, so the only way to close is to force closing on the steam deck.
Initially had a similar problem to gnumaru. Realized I had a gamepad plugged in via USB. Unplugged it and keyboard input worked.
Screen was distorted in the beginning, but minimizing and restoring window removed it. No other problems with graphics detected.

The keyboard controls won't work at all, rendering the game unplayable from the very beggining (I wasn't able to test with a gamepad yet).
Even though some clickteam fusion (the game engine used for these games) hotkeys work (like 'M' for mutting the sound and 'F2' to reset the game) wich indicates that the keyboard input is being recognized at least to some degree, the arrow keys for navigating the menu and the 'z' and 'x' key for confirming and canceling are not working at all.
I have already tried proton experimental, 6.3-7, 6.19-GE-2, with and without steam overlay, using gnome (x11+gdm) and lxde (x11+openbox), and even running directly with wine (6.0.1) but nothing works. I tryied copying some save files from a working windows installation but also without success.
I'm very puzzled that nobody is experiencing the same issues =S.

I have no shame, this game works, have fun
While in a window the game had heavy visual distortion. It was resolved by maximizing the window. Don't know why this happened but it's an easy fix.
I'd say I feel dirty writing this report, but honestly it's not as dirty as looking for reports and hoping it wasn't borked like I did hours before writing it. Now I feel no shame, and neither should you; don't waste your time on feeling shame for what you enjoy in your spare time that doesn't affect others. If you're stuck on and/or willingly using Linux and want some fun, naughty stuff to play, this game works pretty much out of the box.

Proton-5.9-GE-7-ST GloriousEggroll
Glorious Eggrolls proton version https://github.com/GloriousEggroll/proton-ge-custom/releases
i3/tiling window manager issue, you need to get into the options menu and make it full screen again every launch. This is very likely due to the tiling window manager blowing up the screen and thus causing issues. Any stacking window manager might be unaffected but even then it's just a flickering window where you can still see the options menu.

Unable to run in Flatpak version of Steam
I tested this game in both the Flatpak version of Steam as well as the version of Steam installed through Gentoo's steam-overlay. The game will install and start in the Flatpak version, however the Flatpak version will only display a completely black window with the game audio playing in the background.
Worked flawlessly using the Gentoo steam-overlay
I tested this using both the Gentoo steam-overlay and the Flatpak install. This is for the steam-overlay version.