Aesthetically brilliant (albeit inconsistent) and fittingly epic, although I had to throw in the towel on the second boss, sorry gamer '^.^
I feel like a visible health bar and more satisfying hit effects (like a screen shake or impact sound) would help motivate players to keep tackling these tough bosses. Also Bubi's movements feel kinda slow and heavy for a game where you're moving around like crazy, and it makes catching up to the first boss a little frustrating. Once again, a visible health bar to show the player how they've progressed would really help make the grind more satisfying.
All in all, good work!! Keep it up, I bet you can make some awesome stuff :>