I love rhythm games so I was happy to find this in my rating queue! Playing it really reminded me of the game WACCA you can find at arcade cabinets, and I love that game so I was happy to be able to play something similar without having to go all the way to a Round 1. I really enjoyed the charting you made, it was very intuitive and smooth for me to read, and I liked how you put each note judgement rating in the middle since my eyes are going to be drawn there with the direction of the notes, which made all the important information easy on the eyes to find.
I saw your note and some commenters about the game being too hard, and I think a way you could potentially reduce the difficulty is by cutting down the level 1 song time to maybe 1-2 min. so that new players won't get as fatigued and can be more encouraged to retry more quickly (Though I do understand you likely want to show off the full length of the songs your composers made, which they did a great job with by the way!) Maybe you could implement a shorter 'normal' version and have the full version be 'hard' mode?
But I had a really fun time, it's super addictive, and I think it would be a game that I'd buy on steam if you decide to add more to it in the future! :>