I've only been able to get to the second phase (bounce around) of the first boss, it's too difficult to know if/how much you're damaging the boss. It was fun though :)
Gameplay: 4/5, the controls are a bit too "slidey" and the boss is unpredictable
Art: 2/5 initially, but 3/5 after seeing the screenshots, I thought this was placeholder art but if it's minimalist then it's fine. I think you should have added some UI elements, like a boss health bar, or at least attack feedback.
Audio: 5/5, music is great, and BFXR effects are well done (maybe slightly too loud)
Presentation: 3/5, not too much info about combat or how to not die
Limitation: 5/5, quite frustrating :P