Contagion

Contagion is the spiritual successor to the hit Half-Life 2 modification "Zombie Panic: Source". This game is currently under development.

More information will be announced soon!

http://www.contagion-game.com

Zombie Panic: Source

ZP:S is a co-op oriented Human vs Zombie multiplayer survival horror modification for Half-Life 2.

While our main priority is to make the mod as fun to play as possible, ZP:S greatly expands on the core features of the original mod for Half-Life, with the obvious new features, impressive visuals, and of course atmospheric maps.

More importantly ZP:S does not force players to fend against predictable AI, but instead keep the same intense thrill of surviving against intelligent and persistent player controlled zombies.

http://www.zombiepanic.org