As of November 2007 Zombie Horde development ceased and was used untill the CSS 2010 update which then broke the mod so i was asked to make zombie horde reloaded.
Game Play video of v1.1:
Zombie Horde is a server side modification for Counter-Strike Source. It is a game of kill or be killed, occassional bomb work and appalling cruelty to hosties. The game may be played on normal or custom maps, and there are no requirements for users to pre-install any of the files. The server plugin that implements the modification is called zhplugin and may be run on either Windows or Linux Source Dedicated Servers.