Architecture like a 80's tv sci-fi show and a really great layout makes for fun CTF games. The three bridge crossing with transparent walkways is particularly cool. Using fog for something other than a fatal fall was really good to see in this context, but including the BFG is a real killer. With BFG in hand you are almost guaranteed a capture.
Well worth the download, but watch out for that BFG.
Updated - 2nd Ed contains area location entities. (16.sept.2000)