Right off the bat, the start menu / title card was amazing! Having to spin the menu around to see it was unexpected, and it made me smile.
As for the game, it's so fun/nostalgic! Totally nailed the Super Monkey Ball vibes, both in terms of appearance and feel. The controls felt great, other than that I definitely wanted more control over the camera; if I decided to explore and got off to the edge of the map (particularly on level 3 where there is some room to go around, collect stuff, jump off the ramps, etc), then I had a little bit of a hard time re-orienting myself and heading back to the goal. I might also have liked some way to manually do tricks in addition to chaining bonks/jumps.
All-in-all, a really fun little game, and a faithful SMB homage. More levels, please :) Great work!