

Perfeito.
Works great for a little bit, then completely disappears seemingly without reason. Restarting the game fixes it. Happens randomly.

gamemode %command%
Rarely slight stuttering on movement

Basically, the game's main branch has no controller support. However, if you switch to the beta branch (properties>betas>experimental - test builds), you'll be greeted with full controller support. I don't understand why the developer makes no one aware of this, or why he keeps releasing patch notes without any warning that they don't refer to the main branch. On top of that, I can't agree with a game being tagged as verified when the way to play it properly on the Deck is unnecessarily obscured by a complete lack of communication. Great game, but I wish the developer was better at communicating that all of his updates have been exclusively for the beta branch, where controller support can be found.
Perfeito.

Works perfectly out of the box on Steam Deck. I was puzzled to find that I had no sound when I installed it on my Pop!_OS 22.04 desktop.
In my specific case, this was because I'd forced all OpenAL audio through PulseAudio to fix a problem with a different game (Minecraft). This fix clashed with Proton's audio routing.
Anyway, I'm almost certainly a minority of one here, but just in case I'm not, if you experience no sound, any you've already tried swapping out the included version of OpenAL, double-check your ~/.profile file to make sure it doesn't include anything like this:
export ALSOFT_DRIVERS=pulse
If there is something along those lines in there, comment it out, reboot, and try relaunching Moonring.
Runs excellent out of the box!

Worked well out of the box with experimental enabled. I didn't have any real trouble, just a few places where patience was necissary.
Takes a long while to generate maps. The initial generation took long enough that gnome popped up with the "program not responding" window. I Ignored that and was patient for a bit, noticing the music changing in the background still, and after a minute or two it started loading properly. There is also quite a lag when entering dungeons 15-30 seconds I'd say.
The game freezes on world generation.

Proton experimental fixes Steam + X opening the keyboard, but it just seems buggy overall. Unsure if game or not.
Game is keyboard and mouse. Mapping some radial menus, and keyboard keys to face, back, bumpers, and triggers makes for a good experience. Invoking on screen keyboard is needed. Steam + X is buggy, sadly.
Cloud saves don't exist now, but are on the way per the dev

Plays well out of the box
Plays well out of the box, had to manually enter Fullscreen mode during initial start
runs great out of the box
Runs right out of the box with Proton 8.0-3

No issues with proton 8 experimental.