I think its a great start, but as Scote said its missing little details…dust clumps, it looks like a major event happened and then someone cleaned up all the dust. I also feel like all your edges are too sharp giving this a tiny bevel will help make your edges more believable. Think of the straight standard edge you get when you create and object like an infinatly sharp corner. i also feel like the scene needs more material definition everything has the same spec value and it makes everything blend in, I also feel you need to push the lighting more and this would help out the material issue.
Is this real time or prerendered.
but its looking good keep at it man 