I understand you probably want a dull setting,
but I wish there were brighter highlights.
your brightess highlight is a light grey

That looks scary as hell lol, look fantastic though, would look dope asf if you could pull this off for a banner, would look great on my friends facebook page as he produces Dubstep music,
and the gas mask is the theme so would look on point. I'd have to give this an easy 9/10 for you, great work mate.