I really like your portfolio, however I do see some things that could use improvement:
-On your soldier, the bottom of the gun doesn't look as real or as awesome as the rest of your character. I think that peice would be a lot better if you worked more on his handgun. Also I think you could use some time on drapery studies (as could I haha), the folds on his pants don't see accurate.
That's all the critique I have right now, thanks for posting your portfolio.