Very captivating. If you ever attempt a similar piece, here's two things you could look out for. Fielding; even though the camera is tilted, I would rotate this canvas maybe 15 degrees counter-clockwise, because her face, where our eyes are drawn, would almost look as if it were shooting a stare past us. In short, the drama of your scene intensifies. Design; your colours are great, but I think there are too many spirals in the lines of fire. If you space them out more it would look more dramatic and illustrate the motion of the bullets better.
Mind you, my critique is from the stand point of an animator/board artist, so film language is what I'm talking about. But this painting clearly has a story, and an intense one at that, so I hope the crit helps. Very stunning work, mate. I particularly like the design for the boots!