Neat idea, had some fun with it. But yeah, the puzzles could have been better. Like, maybe start a level off with the two characters being on opposites sides of the screen, or up/down etc.
Graphics are really good, as well as the controls. Sometimes though when there is a steep floor, the controls get a bit funky, as in, you would expect the character to fall, but he remains floating in air. The object designs could be improved cause of this.
So basically, good base to build upon.