The sketches themselves are fantastic, but I think one of the best things about this is just how you compiled them together. The background looks amazing...what in the world did you sketch these on - a brown paper bag??
Nice. I like that the three have slightly different builds. To me this makes sense given the different personalities. (I could see Raph contantly hitting the weights as he tries to get rid of built up tension!)
Gonna guess, from left to right, Mikey, Raph and Leo...
I could be completely wrong, but I always think of Raph as being the bruiser of the group, and the one on the end has that rigid posture you would associate with the stuffier Leodnardo. Mike is the one I am least confident of.