Launching with Proton Experimental (as of 3/1/2023) causes a background launch but the game never comes up. Tried also with Glorious Eggroll. Switching to 6.3-8 brings the game up and plays like native.
Short but sweet Resident Evil/Silent Hill type of game
After fully completing the game and playing all of the side modes, I can confidently say this game runs great on linux.
Nightmare of Decay uses one of the newer variants of Mono + Unity, and works very well out of the box
For whatever reason the Steam on Steam Deck refused to download the game 0b/empty folder. I cleared Steam cache, changed download servers, nothing. I think this may be a Steam issue more than a game issue, but I'm noting this here. But I got a workaround by downloading steam on my laptop (Windows 10) and installing the game, then FTP the files over to the Steam Deck's Nightmare of Decay folder.
Had to bind the left mouse click to left pad click, Also had to bind Q since that's used in the game. Otherwise WSAD worked mostly out of the box.
You can enable a Steam 30hz lock for better battery, or use VSync in the game to lock to 60.
Requires Proton Experimental (as of May 5, 2022), Proton 7.0 launched, but the look sensitivity was a bit high (even lowering it to max in-game settings)
I was able to launch and play the game with no issues. I played the demo for about 30 minutes, as well as the full build for another 30 at the time of writing.