This is a cool image and the longer you watch the more cool stuff you see. I first didn't notice that the scary guy in the background was connected to (Or perhaps is?) her shadow! Really cool touch. Further I really like the perspective with which the piece is painted with a solid horizonline at her hips roughly which makes it possible for you to do a much more dynamic picture with nice depth on the ground stretching into the darkness. Very nice. I'll actually try that out myself!
Next I really like the design of the main charecter, she looks ready for battle but she's been through something but is ready. Sort of reminds me a little of Ripley from the third Alien movie. Strong woman ready to kick som butt. Very nice.
The things I have some critique against are the shadows on her face that I think are a bit dark and the lack of detail on her feet. The funny thing is that these are just things that you see in the high-res. In the standard view these things look good so I'm gonna guess you are threading just on the line what is the proper level of shadow. Still, perhaps something you want to fiddle more with in the future, i.e. how to balance the shadows and avoid solid black shadows in covex shapes as that generally does not happen.
The next quirk is the fire, it looks a bit odd and simply think that you should've used a reference for that. Also, it doesn't quite follow the perspective, should have been angled a bit more to the right I think. You could also have been more genorous with the coloring of it, stronger more vibrant color as it is a lightsource after all. The same goes for the background, would have loved to have seen a sky, perhaps a moon that could have cost some pale white light on the main charecters back and perhaps added some white rimlighting. These are subjective comments though and I, at the same time, like your design choices.
In your comment you posed a question about her looking clipped in. I don't really see that, I think she fits well with the background. What you could have done though is to add some yellow/orange-ish highlights to her, especially the pants, as they would be lit by the fire and reflect the colors of said fire If you have made this in Photoshop, add a new layer ontop of everything, set it to color, pick an orange color, fill the entire layer and set its opactiy to around 5-10 percent. It will probably blend the colors nicely and make her fit better by evening out the palette. Also, I think the angle of the shadow contra the fire is what makes her float a little. The fire should have been a bit further to the right to give the shadow that angle. (These points are motivation for 4/5)
Overall though a cool piecce, the brushing, perspective, design are all really nice. Just that the devil is in the details, or in this case right behind you! Looking forward to your next work. Cheers.