On April 21, 2008, the game was released to the public as a beta version. Multiplayer mode and player versus player combat were released on July 15, 2008, allowing players to team up and play the game, or fight against each other. A player-run market system (named the Dead Frontier Mega Mall) was created on October 1, 2008, to facilitate trading among players. The barricading system, used to secure buildings, build personal outposts, and prevent zombies from entering them, was released on January 26, 2009. It allowed players to create their own outposts in the Inner City, where they could access services (market, bank, storage, etc.) as they could in the main outpost. A new inventory system was released on March 15, 2009, along with the ability to conduct private trades. A new market system was also released, replacing the Dead Frontier Mega Mall. Missions were released on July 19, 2009. They gave specific tasks to players, such as to destroy all infected in an area, for a cash and experience reward. Though some missions are glitched the game has an overall high rating within the player community.
