This game is about you, escaping as a scientist from Black Mesa Headquarter, A new building build in 1956. This building we're used to hold some public project. Before you joined as a scientist, you need to do a training on a Hazard Course. The Black Mesa Headquarter is much the same as Black Mesa Research Facility itself.
The Place Where All Selected Recruit are chosen their fate.
I must say you design these outdoor areas rather well. I'd eventually place some minor houses up that wall and rock site to enhance things visually more. Just like it was done in Living Quarters Outbound in Blue Shift. It gave the impression of a vast facility and village like environment.
If that all is nothing then perhaps a tiny ledge onto the rocks slightly above the wall with a small cactus placed onto it. You could even add a small hole or gate up that ledge to symbolize that there actually is some sort of installation inside the rock formation to the right.