Your game has already some interesting stuff. Art and animation are quite good. The idea of rythm for doing combo is a good idea. At first I didn't get it and was constantly running back and forth which was pretty boring. But once you figured out how to do proper combo, enemies in the game made more sense. I think you should definitly design your gameplay/enemy idea around this mechanic as it is surely distinctive compared to other game and could potentially lead to unique stuff.
Congrats for the work !