Pretty neat game! It is a relatively small one, but I still have a couple of comments and feedback if you're interested.
What you did well:
- Great audio, the bouncing piano noise and the ambience fits well.
- The effects as the shapes bounce is smooth and satisfying.
- Having number indicators to show how many bounces a ball has is good
Suggestions:
- The core issue and honestly only thing I'd really want changed is the stuttering and performance. Though I believe from an earlier comment you'd say you would look into that matter so that's good.
- An option to change colors maybe? Think it'd be cool if you could also toggle a rainbow effect where the game slowly changes its color overtime.
Overall, good job!