I'm a jazz / blues pianist and I'm really good at music games so this comment will be 100% biased xD
Loved the game, it felt pretty polished and the theme was well put into it. I liked the last song the most, it felt great to listen to.
The only thing I'd critique is that the audio feedback from the note you play comes a bit before it reaches the bar, I understand that u're supposed to have some kind of audio prediction, my feedback is merely that the prediction is off (should be heard a bit later than it is rn).
Great game!