Some crits on the models from me:
I think you need to work on that anatomy. Pick up some books of bridgeman and gather alot of reference. And study each part of the body separately. I know it's alot of work, but it's worth it! And your designs arent that strong. Try copying a 2D concept you like, after all - that's what you'll do most of the time if you work in the games industry.
Some quick problem areas I saw: The corner of the mouth, the head shape (the skull), the orbital process (eyes). I also miss some sence of weight in the poses. The overall proportions of your models are good! Keep it up man