Nice boss-rush game!
I have always liked boss rush games. In this particular one, I think the game leaked impact. Our attacks, the boss's attacks, and movement could've been more impactful. For example, a frog's landing movement could trigger a screen shake effect. Or our chakrams could give a little directional screen shake.
Instead of the impact, I think a true 64x64 resolution would enhance the looks of this game, but currently, there are many sub-pixels going on considering the rendering type.
Overall, solid entry, good job!