great work, love the sepia mixed with blue. I see you've requested critique so I'm just going to throw in my two cents - first the forshortening is good, but it's a tad off in a couple places - her torso seems slightly too big, as do her upper arms [between shoulder and elbow] - boobs are a little too high, shoulders a little too wide. Also, for some reason compositionally it was difficult for me to notice at first that there was a gun on the left, it might need some contrast with the robot head behind it - seems to be swallowed up in the same tone. There's also something I can't put my finger on in her expression. I think she should be looking at something in particular, or angrier, or something. Right now her expression seems to be just looking off into the background, and that doesn't seem to fit the dynamic action feel of the rest of the image.
Great work though, I can tell you put a lot of time into this, plus i know how hard it is to work huge I think the colors work really well & i love the details of her outfit.