Good job finishing this game!
Presentation and music are incredible, I love them! The main menu looks awesome too. Usually I feel sad to see pixel art sprites scaling and stretching, but in this game it is done perfectly to the overall design.
It super hard to code a rhythm game, and you've got many things right. Small lifehack here: you can record an audio of yourself drumming the table at times when you were going to press a key, and then layer it on top of the music to see if your inputs align with the track rhythm.
"Good" circle placement seemed to be a little off, too far away from the place where it would align with the grey circle.
Hope to see more tracks in this game!