My rhythm sucks so I can't tell if the timing of the game is actually timed with the music, but I don't think it is.
That aside, I find it really funny that Icarus jumps around to attack all the mobs because it's not something I'd typically see in a rhythm game (though I don't play them at all). It adds some dynamism to the gameplay.
As I don't play rhythm games, take my comments with a pinch of salt. I managed to beat the first level just by spamming space, and it seemed like no matter where the mob was within my bubble, I would also get a "Good" rating.
I think "Perfect" should be given if the mobs are at the edge of my bubble, and that the bubble should be smaller to make the gameplay better fit with rhythm. I should also not be allowed to continuously spam space and not be punished for it.
That aside, I really like the drawings, especially the title screen. It is very cute and nice!