Good game, it's a great idea and the ball movement is fluid.
But at some times, it's a bit fiddly, and it feels like the game is harder to control, ideally this would be the player thinking that they need to get better.
Some levels are easy to cheese also, I've noticed a bug where repeatedly jumping on the top of the screen, on some levels can make you fly.
If there is one thing I could change, it would be to make the player character smaller and the levels bigger and more convoluted. Because currently it doesn't really feel like a puzzle, just a platformer.
Some screen shake/sound effects would make the game a lot more fun, feedback on what you do is always better for the player.
Overall, great concept. With a bit of polish it has lots of promise. Considering the Game Jam limitations it's a fun, tight platformer.