Question about a map

So I came across this video browsing youtube one day for garry’s mod maps. I was wondering if ANYONE had ANY idea about it, ide really like to know what it is, and the author of the video hasn’t got back to me so hopefully somebody here can help me out. If you can I would appreciate it alot! Also I wasn’t 100% sure where to post this, but this looked like the right spot.

Wrong section, should be in Gmod GD.

[editline]6th March 2014[/editline]

Personally I’d just wait until he responds.