This is very cool, super impressed with the generative music aspect of it, and the game feels polished in appearance as well. Playing is pretty simple, which made it easy to get started and intuitively understand how the game works after only a few seconds of playing.
One thing I would have liked is a way to feel like I was doing more than just randomly deciding to switch the shape of the cursor - maybe this could be helped by showing the possible cursors (and currently selected cursor) somewhere on the screen? Especially since the time pressure is on, I think having that information readily available would give the player a bit more agency over their score.
Overall this is a very cool concept, and as someone who knows very little about music theory it’s amazing to me that a game like this is even possible. Awesome work!