DayZ

What once used to be a mod for the Arma 3 became a standalone title with the same name. DayZ is an open world survival game, which is based on gathering food and water for survival and weapons and clothing for self-defense. Players are dropped inside the 225 km2 of the fictional former Soviet Republic of Chernarus. Starting with nothing, but simple clothes, flair, and a rug, players will have to scavenge for items, transport, and weapons, while running away from either zeds, bandits or hostile players.
DayZ can be played as a single player game, but most of the current player base is using multiplayer servers in order to form groups, clans and survive together. In order to make the survival aspect more realistic, aside from thirst and hunger, several diseases have been added to the game, with specific cures for each effect. The game supports text and voice chat for communication, with a system that allows not only for a player-run radio station but secure two-way radio, without nearby players to hear it.