Left 4 Dead is a cooperative first-person shooter video game with survival horror elements, developed by Turtle Rock Studios and Valve Corporation. The game uses Valve's proprietary Source engine, and is available for Microsoft Windows, Xbox 360 and Mac OS X. Development on the game was completed on November 13, 2008, and two versions were released digitally: A downloadable digital version, released on November 17, 2008, and a digital retail disc version, with a release date determined by region. The digital retail disc version was released in North America and Australia on November 18, 2008; and in Europe and Japan on November 21, 2008.
Set during the aftermath of an apocalyptic pandemic, the game pits its four protagonists—dubbed the 'Survivors'—against hordes of the infected. There are four game modes: a single-player mode in which allied characters are controlled by AI; a four-player, co-op campaign mode; an eight-player online versus mode; and a four-player survival mode. In all modes, an artificial intelligence (AI), dubbed the 'Director', controls level pacing and item placements, in an attempt to create a dynamic experience and increase replay value.
Left 4 Dead was well received by the industry media upon its release, with praise given for its replay value, focus on cooperative play, and movie-like experience. Several criticisms were aimed at limited level selection and the lack of a narrative. The game has won several publication awards, as well as distinctions from the Academy of Interactive Arts & Sciences and British Academy of Film and Television Arts. As was done with Team Fortress 2, Valve supplemented the game with free downloadable content. The first, called the 'Survival Pack', was released on April 21, 2009. The second piece of DLC was charged for on Xbox Live and came in the form of a new Campaign entitled 'Crash Course,' released for both the PC and Xbox 360 on September 29, 2009.
The popularity of the game led to the development of a sequel, Left 4 Dead 2, which was released November 17, 2009. Left 4 Dead 2 was released on Mac OS X via Steam on October 5, 2010, and the original Left 4 Dead was released for the Mac soon after on October 28, 2010. The Mac version of Left 4 Dead 2 incorporated a new map for both Left 4 Dead and Left 4 Dead 2, called 'The Sacrifice'. Eventually all Left 4 Dead campaigns were ported over to Left 4 Dead 2 and allowing for cross-platform support between Windows and Mac versions.
There are four playable human characters in the game: Francis, a stereotypical biker (voiced by Vince Valenzuela), Bill, a Vietnam Veteran (voiced by Jim French), Zoey, a university student (voiced by Jen Taylor) and Louis, a district Account Manager (voiced by Earl Alexander).[15] Early plans were for players to be randomly assigned to characters but in the final release, players can choose any character—provided that the character has not already been selected—or be randomly assigned an unselected character.[8] Aside from appearances, all of the characters play exactly the same in-game.
Survivors are armed with various firearms. Each player starts the game with a semiautomatic pistol.[16] It may be reloaded an unlimited number of times and is the only weapon that the survivor can use when they are incapacitated. When a second pistol is found, the player can dual wield them, also with unlimited ammo. At the beginning of each campaign, the player can choose between a submachine gun and a pump-action shotgun. As the survivors progress through a campaign, more powerful weapons can be found: the fully automatic assault rifle (an upgrade to the submachine gun), a semi-automatic shotgun (an upgrade to the pump-action shotgun), and a scoped hunting rifle. A flashlight that can be toggled on and off is mounted on each firearm, with the exception of additional pistols. In addition to firearms, a player can also carry three other items in their inventory: improvised grenades (either a Molotov cocktail or a pipe bomb modified with an attached smoke alarm designed to attract the infected to it before it explodes);[16] a first aid kit, which can be used to heal any survivor and pain pills, which provide temporary health that depletes gradually and quicker with damage from infected, and can be handed to teammates for later use. Regardless of what weapon or item a player is using, a melee attack can be used to shove away any infected within reach. Also available are environmental weapons, such as gas cans, propane cylinders, and oxygen tanks, all of which explode when shot. These environmental weapons can be picked up, moved, and used as a melee weapon by the survivors, but while carrying an object they cannot use their weapons or health items. Strategically placed minigun turrets are also encountered at various locations throughout the different maps.
Left 4 Dead went gold on November 13, 2008, and was released on November 18, 2008, in North America; and on November 21, 2008, in Europe to coincide with the tenth anniversary of the release of Half-Life.[59][60]
Valve released a server patch in December 2008 to stop players on Xbox Live from using PC-style cheats.[61] A spokesman from Valve said, 'The fix is designed to halt the cheating behavior on the dedicated servers, which accounts for the majority of the co-op and versus modes of play.'[62]