Great puzzle platformer!
I got stuck a bit on the second last stage, but I finally managed to complete them all.
It was pretty satisfying.
The "mirror world" concept is no more a big news in puzzle games, but it was perfectly implemented here, with a good difficulty curve.
Also nice music and graphics!
Just not to say only positive things: the "radioactivity" theme was just about some radioactivity logos in the scene, not actually part of the game... :P
Other than that, well done! :)