Let me start by saying that i really like where this is going. I've always had a thing for pure black/white.
I think when using black and white it's - and this might just be a matter of style on my end - better to use white to suggest shape, rather than define it. I definitely dig the deliberately dark, almost gothic thing it's got going, but i think there's too much white, and it's sort of distracting.
One thing that black will do is sort of "fill in the gaps" so that you can imply detail without directly presenting it. Of course i'm no art student, and this is just an observation, so i could be completely wrong there.
Here's something I did probably 5 or 6 months ago. I'll probably never get around to making it not look like ass, but it'll kinda give you an idea of what i'm talking about.
and while this probably kills the entire intent of the thing, i thought i'd give it a quick/dirty edit. the upper part of the guys head.
Of course now he looks more frightened than anything.
One thing i noticed while i was doing it is that the guy's chin seems kinda ...large.