Heh, intellectual property is more than just the name. I'd love this mod/game if it was unique and independant content. But this way I am too sad that talented people create content that cannot be "free". Not that it makes your stuff bad, it could just be so much better and reach a broader audience (I know of no free FPS with decent singleplayer/story for example). (By "free" I mean the free and open-source movement.)
But enough of that and to some hopefully helpful criticism.
You have some serious patterns in those "brown concrete" parts, I'd try reducing that or at least aligning it somewhat nicely. The bottom shot has a wrong texture face down on the left.