Love the sprite art and animations. Great stuff. I think the charge attack takes too long to use; it's not very practical for enemies that are always moving around. The only time it really worked for me was when I was able to catch enemies with it as they were falling onto the stage.
Also, I think there was something wrong with the boss. I tried fighting it twice, but both times it just sat there doing noting. I don't see any other comments mentioning this so maybe I was really unlucky?
Either way, I was really impressed by the art. Good job.