Looks pretty damn hot in places but a bit bland in others, but overall it seems like a nice job. I really like the outside alleyway for some reason - nice use of modest details and it comes out looking realistic and interesting. I think the stain decal on the wall around that thing sticking out of it above the ladders does more for the scene than anything else too
By the way (if I don't moan plenty of others will!) those screenshots are ovely large in file size at over 200/300k, and the quality of them is somewhat undermined by the fact you aren't using particularly good looking HL2 quality settings :P If you are gonna redo them, aim for 100k please