A tough challenge for sure!
the speed of the game is quite something, but if you're fast enough, it's quite something!
Excellent implementation of the leaderboards and scoring system (though I wish I was able to get higher than D :c ). Slider moving up and down paired with the notes slowly fading in makes the appearance of new notes excellently smooth.
Criticism-wise, I'd definitely add a level or two on the lower side of the difficulty, because the game feels genuinely overwhelming for some with limited reflex :/ Another thing is the lack of punishment for pressing a note when it's not needed - I could land decent scores by just mashing all the keys as fast as I physically could - there is no safeguard against this kind of cheating. Still, very solid entry, was it not for the low amount of tracks, I could've mistaken it for a fully released game, with how smooth and polished the core gameplay loop is!