Thanks so much for this feedback, I'm glad you enjoyed it :)
Part of my motivation for this was as an educational-style game actually, so I'm glad that went noticed!
Regarding disabling/isolating tracks, that option is on throughout the game. I do see what you're saying in regards to it adding an additional challenge, but I also wanted the game to be decently approachable by people without a strong music background, so having things like isolated tracks and a metronome should help more people finish it. Also since it's a jam game I tried not to make it particularly hard haha