On v0.9.2 I was in the spherical thing with the White Castle in level 2 and got stuck in the squarish indent in the ceiling. When I tried to use R to respawn away from that, I got launched up and far out of the map. When I pressed R again, I was teleported to a tiny version of the map and promptly fell out of the world, this repeating forever any time I pressed R after.
Other than that, great job! Fun and interesting to explore. Are the hams from the bonus levels necessary to progress? They're very difficult.
Ah, I've encountered a few like that with the gravity swapping, thought I'd fixed them all. I'll try and fix that one too! Thanks for letting me know!
The hams in the bonus areas aren't required. There are enough hams to progress without the bonus ones. They are just there for completion and a challenge.