Under is a half-life 2 mod, and you are a citizen named Andrew, who must fight the combine in a city in the united states.
This mod uses some texture of half-life 2 beta.
Try using a variety of textures on the walls to make them more interesting. This con be done with making two separate brushes for the walls, one on top one on bottom; then texturing the lower part of the wall with a concrete that has grunginess at the bottom, then texturing the top part with some dirtiness at the top. That will really help make a space feel more interesting and realistic. There are other things you can do as well, like adding little pillars along the wall, or making out crops for gas pipes and such. What I'm trying to get at is that you should stray away from the plain concrete box.
Try using a variety of textures on the walls to make them more interesting. This con be done with making two separate brushes for the walls, one on top one on bottom; then texturing the lower part of the wall with a concrete that has grunginess at the bottom, then texturing the top part with some dirtiness at the top. That will really help make a space feel more interesting and realistic. There are other things you can do as well, like adding little pillars along the wall, or making out crops for gas pipes and such. What I'm trying to get at is that you should stray away from the plain concrete box.