Man, I had a lot of fun playing this. The art is cute, music is playful and fun, the gameplay is challenging.
I was confused at first about the player projectiles turning maroon and continuing to bounce after hitting an enemy, but it seems like that's probably to keep the player from just spamming balls at the enemies. I tried that in one of my attempts and ended up getting killed by the rebounding balls. Brilliant. I do wish they'd stayed teal colored though.
Overall, I love it. I like the small, square window, and the adorable sprites. Its just a neat little game. A fun way to kill a few minutes. Well done!