I think I notice that you use "full lightmapping". This feature should be disabled as it slows down your game, requires too much performance and consumes too much memory for very little effect.
I see that you like to work with shadows? Good! Thats essential in FPSC as you can make a mediocre scene look fantastic with the right lightmapping.
Here is something you need to learn: Your contrast between really bright lights and pitch black darkness looks off. Try to use very broad lights with really dark colors and some small bright ones close to your lightsource...this will look like real light reflected by its environment and it will make your scene look a lot less "chopped" and "distorted".
You once told me that you work with photos? Its a good thing for a beginner to have some system in his workflow rather than just click around. So good idea on that
Furthermore: your lighting colors are really agressive and I don't think thats the tone you want to go with in this game. I'd suggest to use less strong colors and take a look at the same scenes. Or when was the last time you saw some sewer/maintenance area/subway with extremely green or red lights?
It looks okay so far!
Keep it up
-Wolf