The game initially had some issues rendering the first 3D area whilst using the default Proton or the latest GE-Proton. I had a similar issue with a single level in Sonic Frontiers, so it might just be something with this system specifically. In both cases the issues didn't occur on Steam Deck, just this desktop. Proton Next seems to run the game perfectly. The game runs at 60 FPS solid for me, but I also get a jittery feeling somewhere. It feels like some parts of the game might update at less than 60 FPS internally, but that's just a guess. Overall the game looks and plays very well.