On the green guy. Left leg looks twisted.
Cracking knuckles animation should be a bit slower I think. Otherwise, I recognized it right away.
But see if you can't do a little work on that leg.
Blue scarf girl looks good. Can't see her face like the other guys. Upper torso maybe moved a few pixels to the right. Otherwise it looks just a tad off to me.
Brown white scarf guy looks brown. Make him stand out a bit more. He doesn't look as shaded as the others.
I honestly have no idea what's going on in the animation. If he's shrugging, shoulders are supposed to go upwards.
Other then that, I like the idea. Is this a steampunk/No more heroes cross-over?