i'm not one to tell you to do anything, but i suggest you make more HL2 recreations. maybe next you should do the nexus, or maybe the camp where you meet Griggs and Sheckley.
(if that's how you spell it)

This is a great copy!! omfg You are Extreme..

I used the fog editor to make everything darker, then I used some lamps for the sky light and some normal lights for the elevator and the thumper. For the tunnels and caves, I used a transparent black color on a brick texture and stacked it with stacker tool so it looked like a gradient.

How did you make some parts of the map darker?