Hey!
Gameplay: The idea of the game is fun and engaging! In the first play session, it's a little bit unfair since the mechanics are not that obvious. However, they are super easy to understand, and by the second session, you are already prepared to rock it! Once you get used to the mechanics, how the platforms and projectiles behave, the game has the perfect amount of challenge. Personally, I LOVE games that forces you to constantly move and never stay in the same position (Obssesed Doom player here) played this game a lot.
Art: It is extremely minimalist, but it suits the retro pinball-like concept very well and gives a certain vibe to the game. It would be nice to add a blinking color effect in the red platforms to make easier to predict when the platforms will switch color.
Music: The music is good; I would just give some advice to the composer. When you have boss fights that are designed to endure a considerable amount of time, I would avoid using short loops. Long battles plus short loops equal lots and lots of repetition and can hurt badly the perception of the soundtrack from the listeners perspective. This becomes worse when you consider bosses as sth challenging that invites constant repetition. Being that said, in the realm of videogame music a lengthy and challenging boss fight is your best chance to show off your composition skills in long formats.
I enjoyed playing this game a lot!
Wishing you good luck and success!