I think what amazes me most is your ability to manage the skin tones here. I didn't realize until some recent work with a model, but getting the skin tones just right is unbelievably difficult. In this case you manage to do it without the strong shadows going completely black. If I was going to look for something to critique, I would have to say that the electical box and conduit and the left is too sharp relative to the model and background to the right of the model. The strength of this is the light on the model and it is amazing.
I don't believe the nude belongs against the background - pasted on!
The model was not pasted on. This photograph is legit and had almost no postprocess to it (minor level correction and some spot editing here and there).