Thanks for the feedback!
After the jam I chatted to someone about the note cycling, and realized I could have used, W/S or Up & Down to cycle the notes, stupid that I hadn't realized that when I had time to implement it it would have been way better.
Yeah there should have been a more obvious transition between levels I agree, a sound cue or a more obvious visual transition.
It's just with both these last jams I've taken part in (my first 2 jams using Unity solo) I've had massive issues such as project corruption, level loss etc on the final day of the jam, and have ended up submitting something I haven't got polished enough to the level I'd want it to be. Better than not submitting though, right?
Level design seriously suffered too both in this game and my last as I left serious level design to the last day and then had all the project breaking/data loss issues come up on the same day. I've now started to make commits to Unity collab to reduce the chance of me losing lots of progress, and being able to instantly revert should I need to.