This is a very unique and interesting game, here's what I have to say:
Positives:
1. Unique Game, if you were to extend the concept of this game it could have a lot of potential
2. I really appreciate that the controls for each color are displayed at all times, it really helps
Negatives/Suggestions:
1. Maybe make it so that balls spawn a little slower and less frequent at first, and then get faster later
2. This game needs visual and audio cues for when you lose health and collect score, that might make it more fun as well
3. Make it so the balls disappear even if they made you lose health