The gamemode "Aftermath" is developed by Silverlan, he is the only one who owns and works on this gamemode. This gamemode is based on the game "Fallout3", but using different ideas from The Hl2 Renaissance pack (Created by the same author) and Hl2 and others games. "Aftermath" is a Rpg-like gamemode in which you (will be able to) interact with other players, kill creatures to gain experience, skills, and complete quests. This Gamemode is currently in beta, and is open to the public for now.
This is Aftermath Survival video that shows the concept of the gamemode that is in the works, if you have any questions then don't be afraid to pm with any questions that I can answer about his gamemode.(The video was to big so I had to break it into two parts.)