I think the idea is a cute one, and the visual design is solidly in the right direction. That said, I found it a tad repetitive as there doesn't seem to be any indication of how much damage is being done to you, by the individual enemies - Nor any variance among them.
I'd love to see something like this with some elements that would be useful for decision-making, perhaps turning this into a sort of wave-based strategy fighter! I can imagine it being a lot of fun if there were different attack/defense styles (or perhaps gear?) that would change how you interact with the attackers.