This is fantastic. I love the character already--it's so hard to find playable ladies in FPSes (or in any game, it seems like these days). Seeing that a design like this might be playable (I'm just assuming that she wouldn't be on promo art unless she's either a playable character, or central to the game's plot) is brilliant. I hope your game does well.
Man, I cannot get over how fantastic she looks. And she's in fairly sensible body armor. That's so great. You're getting all of the wonderfully rare brownies this week.
On a more artistic level, I love the way you've chosen to pose her, using foreshortening to give movement to a strong shot of standing still. Hmm, I wonder what your work with more detailed backgrounds is like?