To be honest im not a big fan of lava levels, but I do like the work you've put into the parking area. Perhaps you should have a think bout making a larger 2 level only map consisting out of a parking area. Dont think that's been done b4 (correct me if im wrong) The problem I got with the map at the moment is that it appears repeating itsself from top to bottom. If you're on the top level or some mid section it all sorta looks the same.
On the positive side, I really do get the feelin that im in an empty parking lot, texturing ist all to bad and the scrolling advertisement boards are kick-ass! :P
Id really like to see a more "real-life" attempt at a parkin lot done by you, im sure it would rock.
my 2 cents,