I'm using the desktop version through the Itch app with NVDA running. I've got past the point where you have to hit enter, and so far, the only thing that seems to have any effect is to press R or X on my controller to get a change of note. The others don't do anything. If I leave the controls alone, things change slowly over time, but there is nothing I can do to change it myself.
Oh! That actually sounds right. It initially starts frozen. The default speed is quite slow (one note every eight seconds). At its fastest the notes change once per second. To hear that you can press 9 to set that speed and then E to play (or D-Pad Up a few times and then D-Pad Right on the gamepad). I’m sorry for the confusion.