I think that having typing as an input system for a rhythm game is super fun, and it works decently well here.
It was, however, unclear to me if I was supposed to be pressing the note only for a tiny blip of a section or if I was supposed to hold them down. Holding them down sounded way better so I assumed that's what the game wanted, but it doesn't seem to say anywhere.
It was also always impossible to know what the next node would be on the first page (although, given there's only one song, it should be possible to memorize them, I suppose). This is kind of neat as it does match how sheet music actually works, but it also doesn't necessarily make sense as, although our in-universe character would have practiced the music and so would have either memorized the first notes or written them down or used some other technique to know them, we as the player do not actually have access to the ability to know them ahead of time. So it is actually somewhat out of character to not give us direct access to the note data without us needing to memorize it, if that makes any sense.
I also feel like I may have experienced some keyboard ghosting issues or something? Or I might be thinking of the times when I had to switch between shifted notes and non-shifted notes. It's not really possible to play "legato" when going from one to the other, because shift determines which note it is, so you have to be holding it exactly for the notes that need it.
The one other small complaint I have about the interface is that there really isn't any visual feedback--I can't tell if I hit the notes on time or not. I suppose this is, as always with rhythm games, at least in part a skill issue--if I trusted in my ears, I would simply be able to tell audibly whether I played the notes correctly!
One thing I really liked was the way the conductor would look at us to signal that the play/don't play signal was about to change. That was really cool.
I did manage to do pretty well on my second attempt and I think I had fun! It is quite satisfying to execute the notes correctly, partially I think because of the keyboard interface. Playing chords is especially fun.
Good job!