It’s the first Half-Life modification where I participated. It’s a project that’s been initiated on http://www.twhl.co.za, practically anyone who wanted could make a room and then the person who managed the entire project ( Captain Terror from TWHL) would include in the a chain of interconnected rooms. A lot of this kind of projects have failed, but this one resisted.
My map( a dedication for MuzzleFlash,now “The Mighty Atom” from TWHL) was too large and had too many features to be included in that chain, so it was included as a bonus map. You can acces it from the “portal map” where you can see the credits, play the mod, and other things. My map is represented by a spinning globe, near a “Jim Carry” flag( my avatar from TWHL).
Have fun playing!