Now that the demo for Snouty And The Great Rift has been released, I have been able to get an impression on the game's compatibility with the Steam Deck, thanks to some very helpful testers. In short, the game works perfectly well on the console, but more specifically:
All of the game's functionality is accessible through the Steam Deck's controls, with no additional configuration/hardware required
Button glyphs for Steam Deck controls (e.g. on interaction prompts or when approaching an NPC to talk to them) appear correctly
The game performs well on the Steam Deck with no major graphical bugs/stutters
All UI elements and text appear legible on the Steam Deck, with none clipping outside of the screen's borders
If you are playing the demo on Steam Deck, I'd be interested to hear more about your experience so that I can continue to keep the game as compatible as possible with the console.
Happy foraging!