I always enjoyed the skaven in war (the most technologically advanced race). Yes, the head shape is wrong. I'd reference a skaven without a the helmet for accuracy. I guess it's like if someone never saw a human and tried to model the head based on a a knight wearing a suit of armor. When he's fully armored it won't matter…
The modeling is all and well, but why would he wear such hi-tech armor and such regular/normal boots? Doesn't make sense for a space-marine, try to make something more interesting. I like the top-part of the armor not really sure about the armor on the side of the legs, depends on what detail will go in there. What kind of…
The problem with this character is that alot of the body is being lost in the armor. You have a head, but his helmet doesn't seem like it's sitting on a skull. And the same thing goes for the shoulderpads. I guess what I'm saying is, you have armor, and form, but no anatomy upon which they're based; try starting with a…