That was awesome! With this theme I've seen a lot of entries where people simply take away a mechanic without providing a different, interesting way to play, but that's not the case with this game. Trying to tap in rhythm while avoiding the bullets was a fun challenge.
But the best part is, you didn't just have players tap in rhythm to fire and call it good. You actually put some thought into how the game is played. The targeting system requires you to get close enough to the enemies to eliminate them. Combine that with the fact that an enemy's bullets disappear once they're destroyed and it pushes you to play more aggressively and stick close to the middle so you can take enemies out before their bullets overrun the screen. The countdown as you hit the enemies is a great touch that adds to the rhythm feel of the game.
Excellent work with this game!