I really liked the concept, it's hard to come up with something fresh in a genre so old ;d
I've got a few suggestions on how to improve the game:
- the gameplay doesn't evolve at all, which is a shame. Something to spice it up would really go a long way, maybe some timed powerups that disappear after a few seconds that speed up the charge time? it would push players to move around more and risk a bit, making the gameplay more interesting,
- the music is very repeptitive, but sfx is very good,
Other than that, a very cool game, simple, but made with care and completed on time, which is amazing in itself ^^