Left 4 Dead

Left 4 Dead (also abbreviated to L4D) is a first-person shooter survival horror series developed by Valve Corporation and Turtle Rock Games, and published by Valve (online) and Electronic Arts (retail). It is based in the days after a pandemic outbreak of a viral strain transforming the majority of the population into zombie-like feral creatures, the games follow the adventures of four survivors attempting to reach safe houses and military rescue while fending off the attacking hordes.

The games encourage cooperative play between up to four players, each taking the role of one of the survivor characters and the computer controlling any unassigned character. Players use a combination of melee weapons, firearms, and thrown objects to fend off attacks from the bulk of the infected creatures, while using an assortment of healing items to keep their group alive. Certain unique infected creatures pose a more difficult challenge, typically requiring teamwork to take down effectively. The games are overseen by an AI called the Director, designed to give the players a more dramatic experience based on their performance, penalizing players for stalling while rewarding players with special weapons by taking riskier paths.

Left 4 Dead
The first game of the same name is a cooperative first-person shooter survival horror game. The game uses Valve's Source engine, and was released in November 2008 for Windows, Mac OS X, and Xbox 360. 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.

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 plans on supplementing the game with free downloadable content. The first of these, called the "Survival Pack", was released on April 21, 2009. The second piece of DLC was charged for via 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, as well as No Mercy being imported into Left 4 Dead 2, allowing for cross-platform support between PC and Mac versions.

Left 4 Dead 2
Left 4 Dead 2 (abbreviated to L4D2) is the sequel to L4D. The game launched on November 17, 2009, for Microsoft Windows and Xbox 360 in the United States and November 20 in Europe; in 2010, Left 4 Dead 2 was made available to the Steam client for Mac OS X. It builds upon the cooperatively-focused gameplay of the original and uses Valve's Source engine, the same game engine used in Left 4 Dead. The game made its world premiere at E3 2009 with a trailer during the Microsoft press event.

Like the original, Left 4 Dead 2 focuses on four survivors fighting against hordes of the infected, who develop severe psychosis and act zombie-like. The survivors must fight their way through levels, interspersed with safe houses that act as checkpoints, with the goal of reaching a rescue vehicle at the campaign's finale. The gameplay is procedurally altered by an artificial intelligence engine dubbed the "Director" that monitors the players' performance and adjust the scenario to provide a dynamic challenge. Several new features have been introduced: new types of infected, melee weapons, and a story-arc that connects the game's five campaigns together.

When it was announced, it received a combination of positive and negative critical and community reactions. It also attracted an unusually high volume of pre-release controversy about the game's graphic content. In response, alterations were made to the cover art and both Australia (due to having no R18+ rating) and Germany refused to rate the unmodified edition.

Role in Moments with Heavy
Left 4 Dead is one of the recurring gags in the series, such as Francis and Louis making appearances in select episodes. Blue Heavy has also been seen with L4D2, which was the basis of Heavy's Retarded Holiday. Francis has only been on the series twice, Louis once. Louis was seen with an irrational craving for pills, and Francis was seen as a recurring troublemaker.