It's dick is a chaingun... Okay... Cool, but still kinda weird...

I love blender

I'm going to guess the extremely realistic-looking smoke was done in GIMP, because it would be so hard to do in Blender alone. I do like all the extra features in the room, like the crates, the barrels and the gas tanks. The cracked tires texture is also very realistic looking. That blue-marble look for the gun and the supports is a bit odd, neither a reference to a real manufacturing practice nor stylistically consistent with the dark nature of the rest of the robot. And why can't we see his head?

Really, I think that you have my problem in that you know exactly what you want the models and textures and lighting to look like for each object, but you're having a little trouble making an ensemble. I don't advice for that. But I do feel like this image isn't dark enough to be noir, nor bright enough to be caricature, nor detailed enough to be still-life. It's like Half Life 2 but with too much color, and I'm just not sure what "sense" you're trying to convey. By no means a bad image, but I can see why you are "not satisfied with it". (BTW, I love your other 3D work, too.)