First image:
The frames of your caves are using a Half Life 2 metal texture and the windows on the far right of the screen are also a Half Life 2 texture. You have karst and alpine rocks on top of a desert cliff, which stand out from their natural ability to form and the colors of the cliff itself. There's also an insane amount of bloom past the train.
Second image:
Very open. Other than the not-as-solid-as-they-may-appear props you have in the aisles, there's no real cover to hide behind. Once a team takes control of the central structure it will be impossible to break their defense, and snipers can fire right through the whole cave from the entrances. The cave wall texture you're using is a Half Life 2 texture, and there's no way that hole isn't carved.
Third image:
You have a brick pillar supporting a cave system, and small brick steps transforming into metal staircases. The ammo kit needs a patch beneath it. I disapprove of using payload signs in a non-payload map.
Fourth image:
Again, sightlines. Your pickups also do not have patches here either. I can see holes in your displacement around the point as well. Also, who would put up posters in a cave where they would easily deteriorate from the moisture, even if they manage to stick to the solid rock walls in the first place. And also, someone has gone through the effort of hanging lamposts from said solid rock and then running wiring to them.