The 3D shading effects you put into this head are great, it looks fantastic. The only thing I'd say would probably be the "earpieces", which don't really go along with the front visor piece very well. Still, really well done, great job.
I like your shading on the metal parts, but I absolutely hate the way you did the visor. Depending on what program you use, there are many different ways to give a glass-like effect to the visor. In the game, the visor is bright, and not dark in the middle(thats just the shadow in the reference picture.)
Um.. The visor is always like that? I shaded it that way and that picture is taken ingame? The strap does go all the way around the head. Look closer at your reference pic. Are we seeing the same picture?