Glad you enjoyed the game! :)
I see a few complaints about the notes and while it didn't cross my mind in development, I can now see there is a bit of a problem with this one, the shadow idea you suggested seems great.
On the speed up/ slow down, we have noticed that speeding up, especially in first level makes the game way easier and slowing down often is not worth it, I tried messing with the numbers, but it still needs more polish.
Thank you for the feedback and the time you took playing our game!