Minor issues with animated cutscenes, small text, and fullscreen cropping, but overall still a good experience.
Set TDP to 3W and GPU clock speed to 200MHz
Text is a little small and in a handwritten font that doesn't work very well with the Steam Deck's screen.
Game maintains its 16:9 aspect ratio while filling in the screen all the way, causing slight cropping at the edges of the screen. It's not enough to cause issues with gameplay, however.
Animated cutscenes (like the clock hands moving in between certain scenes) do not play and show a white screen instead. Audio still plays, however.
Hopefully someone smarter than me can figure out fixes for the cutscenes and maybe the cropping, but as it is, I think this is just fine. Heck, most people probably wouldn't even notice these issues on their first playthrough if they didn't have a Windows PC to compare against.
While the default controller layout works, I think a custom layout would make the experience just a little better if you're willing to put in the work for it. The game isn't some super intensive action affair though, so it isn't necessary.