The browser version of this game does not seem to be working but the download that can be found by scrolling down does. This game is definitely worth playing and well done for completing it.
Some technical criticisms would be: 1) If you press both dimension switch buttons at the same time you get some objects only meant in one world in the other. 2) If the player rubs into corners while moving he rotates. This fixes itself but it can be prevented by going to the constraints in the Rigidbody2D and checking the lock rotation z box.