Man, I like that boss animation. He's got a variety of moves with good telegraphing, too. Great design.
I want more juice in the graphics tho. It would be nice to have a few frames of animation (particle effects or a white flash or anything) to show the boss and the player taking damage. I think the player's move set could use a little tweaking too, but honestly the problem could easily be that I'm just...not very good at video games :).
Really cool game. I hope you keep working on it after the jam because I think with a little tweaking it could be just epic! That boss is so well done.