I love the neat visuals and the soothy atmosphere of the game ! Clever gameplay idea also, and the platforms revealed by the yellow layer at the end of each level is a nice detail.
Maybe one point, for the level with the long jump (level 4) it feels quite random because we still haven't switch the background even once at this point in the level. I don't know it was intended or not. And also is there any way to restart a level ?