Really cute game. I liked the sounds, the music, the design. Very cool.
It did feel like the switching didn't really make much of a difference. It just changed the look, but both "platformers" were pretty much the same. Maybe if one was on the ceiling, or they had to be done in a specific order because actions in one "world" affected the other? I think that would have added some nice depth to the game.
That's more a suggestion if you keep going forward with the game that it is a criticism. This is a solid little game. Nice work.