This map seems pretty rushed. Here's some feedback.
-The transition between concrete and wood here just looks odd. Why not make the whole thing one or the other?
-I can hide buildings in these rocks. Only really works for mini's and teleporters but will also hide sticky bombs.
-messed up render order. This happens sometimes, try messing with the brush a bit and using compilepal for a full compile. Its the most I've found to do about fixing this kinda thing.
-The rock going through this concrete doesn't make sense. Also the odd lip on the bottom of the ramp is weird.
-You're going to want to use an info_lighting to change the light origin of this prop.
-These displacments don't line up.
-The clipping in this area is really odd. I'd expect to be able to get to the crates but the clip brush is right farther in front of it.
-Big and empty.
-Really easy to see where the change between in game and skybox is.
-The displacments out here are nice, though a few are misaligned, but you could use some rock models and such to make it more interesting. Look at badlands and see how they do it.
-Again, big and empty
-Make this railing nonsolid and use a clip brush to stop players from walking through it. Shooting through railings can be annoying so this is how they're pretty much always done.
-Put some clipping on these planks.
-That's a REALLY long sightline with no cover.
-The clipping for these stairs doesn't go all the way up to the concrete.
-Those are some chunky stairs.
-the angles on these raised areas are difficult to walk on. Simplify it.
-Change lighting origin.
-Concrete on the ceiling of a wooden building? That doesn't make sense.
-This bit of concrete is really weird just hanging out here. It's the only thing like it in the room.
-Misaligned textures
-Really short door.
-I don't think these lights should be bright for the time of day this map is set.
-Textures misaligned.
-This is a heck of a choke for the first point. I'd suggest adding a flank on the left through that rock area. Some kinda tunnel or cave thing.
-There are no flanks here for attackers at all, just one path for everything to go through. I imagine it plays like a meet grinder which is rarely fun.
That's all for now, best of luck.