I see a nice mix of X-Men and Avengers in here. Great fun!
It's not the hardest puzzle game I've played... only one level caused me to check the walkthrough... but most of the levels are easy with a little trial and error. You've done something creative with the genre, however. That's important. The character designs are awesome.
You do develop a pretty good story at the beginning, as well as funny dialogue between the characters was a little disappointed not to see an ending sequence other than the credits. In fact, I almost expected a boss on the final level.
It also seems that certain users aren't making past the comic book intro to the real game. Hope that doesn't hold the game back.
I can't help but feel you can do more with these characters. They may deserve an RPG or a platformer of some sort.