Hey, this is a pretty neat idea! I like to see how people imagine a game as a movie.
The snowy/dusty effect along with the scratches is a nice detail- it gives it a more "gritty" feel. Also the fading out of the figure at the bottom right is a cool detail. It makes me think there is a large source of light off in that direction that the viewer can't see and it makes me wonder what it is. (Maybe an explosion?) I always enjoy that in art- those little things that make you feel as if there is more going on outside what you can see.
The only thing I might do that I feel would enhance this image is to make the figure of the man darker or add some contrast to him. Something that might make him stand out from the background a little more. All of the colors here are sort of faded which I think works with the feel you're going for but I would be interested to see the man standing out a little more, especially as the main focus of the image.
That might just be me though, wanting to see what it would look like. :0 lol
He certainly looks best on the layer you have him though- behind all the dust/scratches. He seems as if he's walking through the debris towards the viewer. If he was in front it might look more pasted on and wouldn't have the same effect so I think you definitely made a good decision with that.
Hope this helps if even just a little! Keep up the good work!