I liked the switching of worlds a lot, the animation for it also feels great. I think I got soft locked in the third or fourth- level about the changing in flight, I just couldn't find the way to get back on track to finish the level? The controls also feel kind of counter intuitive because when your trying to move in the air and press E you have to let go of D so you can't really move right while changing.
Other than that I liked it!