Red Dead Redemption: Undead Nightmare

Red Dead Redemption: Undead Nightmare is an open world, western action-adventure video game developed by Rockstar San Diego and published by Rockstar Games. It was released for the PlayStation 3 and Xbox 360 consoles on October 26, 2010, as a downloadable expansion pack to Red Dead Redemption. The game follows John Marston as he searches for a cure for an infectious zombie plague that has swept across the American Old West.

Undead Nightmare is played from a third-person perspective in an open world environment, allowing the player to interact with the game world at their leisure. The player can travel the virtual world, a fictionalized version of the Western United States and Mexico, primarily by horseback and on foot. Hordes of zombies traverse the world, often attacking towns. Gunfights emphasize a gunslinger gameplay mechanic called "Dead Eye" that allows players to mark multiple shooting targets on enemies in slow motion. Two gameplay modes were added to Red Dead Redemption‍ '​s online multiplayer mode upon release of Undead Nightmare, allowing up to 16 players to engage in both co-operative and competitive gameplay in a recreation of the single-player setting.

Upon its release, Undead Nightmare received generally positive reviews. It won year-end accolades, including Best DLC awards from several gaming publications. A Game of the Year Edition, bundling the game with Red Dead Redemption and all additional content, was released in October 2011.