It feels a bit too HLDM-like, try using more CS textures as they usually look better than HL tex's.
The lighting in the orange corridor near bomb site B is extreme, for light_spots set the Inner Angle to less than the Outer Angle to get a fade at the light edges, try 24/96.
The env_beam rain sprites aren't too noticeable. Replacing them with an animated rain sprite would prolly look a lot better and take less time to do. Jinx has a nice one on his site -
http://www.cryotank.net/
Try and make the next map a bit more realistic as the better CS maps seem to have more real world type buildings, vehicles, layouts etc.