Not gonna lie, it's taking all of my willpower to ignore that her arm cannon is on the wrong arm, but I'm just kind of OCD like that. No, the half a star isn't for that. I'd have only given 4 whole stars if it were. The pose just seems a bit silly to me, that's all, but not much.
ANYWAY, my minor criticisms aside, this is actually very well done. Simple background, interesting designs for the power suit and the arm cannon (I love how the cannon seems to feel organic), and as other users have pointed out, the shadow effects are stunning. Well done!