I love that there are collectibles in both worlds! The obstacles become items and vice versa!
The jump wasn't as good, I would make it a little more reliable, it seems like if you tap it you can't jump over much and you have to press and hold to jump the actual height needed to reach things. I'm not sure if this was put in as a feature but it might be out of place when you mostly need the full height jump.
The sounds and visuals are very well paired together and there was a great explanation of how to play in-game.