These are pretty good. The only thing that looks off is that the two on the right seem to have a condensed upper body area. It feels disproportioned to me. If you were aiming for something stylized then that doesn't matter. I just wanted to point out that, as an example, the guy's upper body is too lard in places and not stretched out enough, or something. I actually can't tell which direction to take it. Sorry I couldn't explain that better.