A good quick way to get something nice looking is to darken the diffuse lots and really brighten the specular for metal areas. then add scratches to specular and tweak, tweak, tweak ;)
Hm, compared to the characters, I believe the environment assets need a lot more texture work to read well and look believable. I'm not sure whether they're supposed to be concrete or metal, I think you were aiming for the latter? If so, I'd really darken the diffuse texture and leave the specular to show the scratches..…