Stage 11 switch: That's what I suspected. Funny how you can get so used to something being a part of the stage that you don't realize when it's lost its purpose.
This is one of those kinds of games that you could easily come up with new twists for, kinda like BoxBoy. Good on you for not letting feature creep derail it. With that said, I'd definitely play a sequel with twice as many levels, especially if you ironed out a few of the little kinks.