Very cool idea - kinda reminds me of the one-man band animations.
If I had to nitpick one thing, it would be that the notes don't always seem to line up with the beats in the song - could just be wonky webGL audio though.
Thank you! Yeah there were some problems with getting the audio to always sync up, especially the WebGL build. I put some checks in place to preload the audio and only start spawning the notes when the audio actually starts, but I guess you can't catch everything. Real rhythm games have an input latency adjuster for a reason!
Also, great work on your game it's super impressive!