A few points of feedback:
- The keys you have to press are only shown once you press them, requiring trial and error unless you look at How To Play first.
- It feels weird to me to press keys that are far apart to hit notes that are visually close together.
- It needs a timing offset to sync the music to the gameplay. I had to purposefully delay my presses, or... play without music, which immediately improved my accuracy (49% -> 73%)