This is a pretty good concept, although I found that the levels didn't actually create any challenge. The only thing I had to do was swap when I hit a dead end. You also never really utilize the restart on death mechanic, the character goes back to the start, but it never really impacts the game, other than making you retrace your steps.
Also, it wasn't anything huge, but the switch prompt is displayed behind the background, so you can't actually see it. I already knew how to flip a switch, so it didn't really effect anything.
Overall you have a good mechanic, but the levels aren't really doing anything with it.