When taking screenshots do you have the grain filter on in the video options? I think the screenshots would look better without the grain effect.
On this screenshot the light only hits the table and the generator next to it but the ground gets none of the light, I think it would be worthwhile to do a improvement pass on the lights. I would take a look at how Valve constructs their lights to make it go as fast as possible.
The light baked into the texture of the skybox contrasts harshly with the surrounding environment, I would investigate using a more dim skybox texture to match the lighting of the level.