This is a super fun concept, I love the idea of scooping up projectiles and waiting for just the right moment to let 'em rip! I think having the glass be destructible rather than solid objects would not only be more satisfying but make it a bit more evident what you're supposed to do in the first level.
The other big suggestion would be to have the yellow disc actually rotate in the correct direction rather than just flipping the sprites inside it - would make it a lot more clear as to what's happening.
Overall though, a great idea and I honestly hope you polish it up and expand upon it post jam. I'll be keeping an eye out!