Mm. I love this. I love the way you did the girl on the left. She looks great. That mock Dr. Doom guy with the green hair instead of hood is great too. Never seen that character before. Love the monster below him, that is megacool. The subtle but powerful diagonals going thru this piece make it more fluid than it would have been had you not put in those powerful diagonals!
And nice job with the green fading into brown.