Updated

still doesn't look like metal :/

ah tablet was surprised to think this was mousedrawn
anywais this head is very sexy.That dirt on the plates give it this nice look in my opinion
ok its nicely shaded and well mapped totalyy deserves positive comments from everyone.

Pigking: not burns
Freelancer: how to make it more metal like?
Ghiita: <3
Please more Crititizm

Uhh. Looks like I have to criticize that.

It looks pretty nice, but what is it? It doesn't look like a space marine at all. The 'face' looks almost organic. He seems to have eyebrows and skin with wrinkles. The metal plating looks like flesh or cloth, not metal.
The upper part looks poorly mapped, it should continue in the back. Also, those platings look pretty random, far away from usual space marine helmet. The eyes are way too round and big.
Next time, look at some references if you want to do something you haven't designed yourself. Here's some:

http://4.bp.blogspot.com/_UpvBe1k6T1...e_photo_01.jpg
http://fc01.deviantart.net/fs50/f/20...ardlynch77.jpg
http://fc09.deviantart.net/fs51/f/20...ardlynch77.jpg

Thanks for inspiring me to do a space marine head.

Edit: You have done pretty well. I see mapping a space marine helmet on a sphere is almost impossible.

also had a hernia when i saw the lack of accuracy to spacemarine design...
and with the texture you added to the plating, it looks like youve had this marine doing mechanical work underneath your car for a full week. looks like he's covered in grease