There was supposed to be a mandatory tutorial that explains everything including how to use the shop but I forgot to add the code to trigger it. XD
I appreciate all the feedback! There's a whole lot more I wanted to do, including combos so I totally agree that's a good direction. The bosses are tied into the story part of the story mode but that's rather problematic with the input issue so my bad! It was sort of a last minute thing but I think a more explicit method of triggering them would be better.
Anyway thanks so much for playing!