Zombie Panic Source
Zombie Panic Source 1.0 is available as a free download on our software library. This free program is an intellectual property of Zombie Panic Team. The most popular version of the software is 1.0. This download was checked by our antivirus and was rated as malware free. Hl2.exe, Steam.exe, Zombie Panic Source 2.1.exe, ZombiePanicSource.exe and zps.exe are the most common filenames for this program's installer. Zombie Panic Source is included in Games.
From the developer:
The basic idea of Zombie Panic is to create solid gameplay that is based on a classic zombie outbreak scenario, the living dead are coming for the last remaining humans, and these survivors must fight them off and live through the day. Everyone joins a server, in the beginning you can either choose to join the human team or you can volunteer to be the first zombie. If no one volunteers the game will pick one human randomly and the game begins.
You may want to check out more software, such as Source Insight, MapGuide Open Source Release or Counter-Strike Nexon: Zombies, which might be related to Zombie Panic Source.