Super cool with the way it puts the music in the foreground when you have to listen to be able to engage fully.
One problem is that the inviorment i very busy and the song would need need a beat that signals what key your on. Let me explain:
1 2 3 4
On the one beat you can jump, on the two you can move left, on the three beat you can jump and on the fourth you con go right.
The different actions for the different beats should be sound coded and those sounds should be pretty loud. For example the jump could be signaled by a kickdrum, the right by a snare and the left by a hihat. That would make it instantly hearable and removing the arrows and having a simpler first level would put the music even more in the foreground.
Design 5/5
Everything works so smothly when you figure it out when you should be pressing the keys. The movement system is super cool and the attack thrown at you just boosts the experience and makes you focus even more!
Adherence 4/5
There is a lot of things that there is only one of, one guy, one tempo, one button.
Originality 5/5
I have never seen a game even close to this before. This is very original