I really like the switching mechanics! I think the button layout was a bit cramped for one hand but I found that I could also use mouse buttons and that helped a bit. One thing is that the frame rate seems to be very unstable if you move through the first areas fast. :C I'm not sure if it's reloading the level every time you die or not, but it does make it to where it's unplayable unless you reload the game. Aside from that, the graphics are very nice and the animations feel zippy.
Well done!