Man, I still have some of the original black and white comics of the Ninja Turtles. The model looks good. Only thing that looks odd to me is the where the leg connects to the torso... seems a bit to narrow or like there is no hip.

Rather than grayscale, why not use basic colored shaders. If you going gray, then I'd vote for all gray, i.e. no colored bands.

Look forward to seeing the move. Will the demo be viewable online?