Great technical demo, but the usability feels unpolished. So here's a little bit of feedback of trying this out on a piano: Just because my piano has 88 keys doesn't mean they are all useful for ear training. The very low and very high notes shouldn't be used, at least not by default. Also they don't even show up properly in the sheet.

As the melodies get longer and longer with each win, this devolves quickly into a memory game. I'd like to keep playing ear training, but I struggle with remembering what sequence of notes came at steps 8+.

This is somewhat aggravated by completely resetting the current level and replaying the whole melody after a single mistake. If I keep making a mistake in note 10, I get all the notes over and over again, which is a bit maddening.