A nice complete game with lots of ideas! In terms of ideas for improvement, it might be cool for the various boss powers to be earned / learned one at a time, or have which one you have access to be tied to a level or story. I wasn't sure what the benefit of each was and felt like I was guessing (which wasn't bad, but there might be a way to make it more fun if the player has to learn how to use them best against certain heroes or something like that.)