Wales, Matt (August 4, 2021). "Left 4 Dead 2's survivors join Zombie Army 4 as playable characters". Eurogamer . Retrieved December 21, 2022.

Versus: up to four other human players take control of various Special Infected to try and prevent the Survivors from completing a stage. Special Infected are randomly assigned to Infected players; they cannot control the Witch or any Common Infected. Occasionally, as determined by the AI Director, certain players will become the Tank. The two teams swap sides once per stage, and are scored based on their stage progress as Survivors. If both teams make it to the saferoom with all four Survivors, a 25-point tiebreaker is awarded to the team that dealt the most combined damage as Special Infected.

On August 20, 2015, an update for the game Zombie Army Trilogy was released, which imported the eight survivors from both Left 4 Dead games into ZAT. [115] In 2021, the characters were added to the games sequel Zombie Army 4: Dead War. [116] Mutations [ edit ] Left 4 Dead 2's new box art: no longer flipping off the UK". Game Grep. 2009-08-06. Archived from the original on 2009-08-20 . Retrieved 2009-08-15. Left 4 Dead contains four game modes: Campaign, Versus, Survival, and Single-Player. Campaign consists of up to four human-controlled survivors who attempt to make their way between safe rooms and eventually to rescue. In this mode, the special infected are controlled by the AI. IGN PC: Best Multiplayer Game 2008". IGN. Archived from the original on December 20, 2008 . Retrieved December 20, 2008. a b Valve. Left 4 Dead 2 (2.1.0.7ed.). Valve. Level/area: Dead Center, Stage 1. Rochelle: I was...down here covering a news story. I'm from Cleveland. / Ellis: Yeah? How d'you like our city so far? / Rochelle: Um...it's lively. / Ellis: Yeah. Well, it's normally a lot nicer when we don't have the zombies.

Weaponry has been extensively expanded to combat new and old foes. Aside from additional rifles, pistols, and shotguns, the game now includes melee weapons such as a chainsaw, a guitar, and a baseball bat. A laser sight that can be utilized to improve weapon accuracy is also new, as are two types of special ammunition. In addition, the Boomer Bile can now be launched at foes, turning the rampaging swarm against them. Maltrapa, Gus (2010-08-13). "Valve Hypes Up Homegrown Left 4 Dead 2 Maps". Wired. Archived from the original on 2010-08-17 . Retrieved 2010-08-13. Turi, Tim (2009-11-17). "Left 4 Dead 2". Game Informer. Archived from the original on 2009-11-22 . Retrieved 2009-11-18. Callaham, John (March 22, 2007). "Left 4 Dead Interview". FiringSquad. Archived from the original on January 18, 2016 . Retrieved September 1, 2008. a b Plunkett, Luke (2010-08-21). "New Left 4 Dead Expansion Lets You Choose Who Will Live Or Die". Kotaku. Archived from the original on 2010-08-23 . Retrieved 2010-08-21.Left 4 Dead uses Valve's proprietary Source engine, with 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 dubbed the " Director" controls level pacing and item placements in an attempt to create a dynamic experience and increase replay value. Oloman, Jordan (September 15, 2020). "Valve builds entirely new 'Left 4 Dead 2' campaign with the community". NME. Archived from the original on September 17, 2020 . Retrieved September 16, 2020. Chalk, Andy (2009-06-03). "Valve Fans Form Left 4 Dead 2 Boycott Group". The Escapist. Archived from the original on 2012-04-02 . Retrieved 2009-06-04. Left 4 Dead received recognition as one of the best multiplayer and PC games of 2008 from various organizations and gaming publications. The game was named the Best Multiplayer Game of 2008 by IGN, [120] [121] GameSpy, [122] Spike TV, [123] NoFrag [124] and BAFTA; [125] and as the "Computer Game of the Year" by the Academy of Interactive Arts & Sciences (AIAS), [126] Spike TV, and Bit-tech. [127] Other awards include " Outstanding Achievement in Online Gameplay" from the AIAS (who also nominated it for " Overall Game of the Year"), Best Use of Sound for the PC [128] and Best Shooting [129] game overall from IGN, Father of All FPS from Nofrag, and the best Cooperative Multiplayer [130] and Shooter [131] of 2008 from GameSpot who also nominated it for Game of the Year.

A far simpler version of the A.I. Director was previously used for some key battles in Half-Life 2: Episode Two. [21] Valve is looking for ways to apply the Director in their future games to make pacing and difficulty more dynamic. [22] Game modes [ edit ] Left 4 Dead 2 Interview: Chet Faliszek - Gamespot". GameSpot. 2009-06-03. Archived from the original on 2015-11-19 . Retrieved 2009-12-05.a b Mitchell, Jason (December 4, 2008). "The Moviemaking Process: Left 4 Dead's Intro Movie". Valve. Archived from the original on March 1, 2021 . Retrieved December 6, 2008. Left 4 Dead Afterthoughts". 1up.com. Archived from the original on January 18, 2016 . Retrieved January 19, 2009. We actually started out with a single, huge city design with a great many routes for the survivors to take to reach the extraction point. As we began to playtest in this zombie city, we immediately discovered that having that much choice combined with the chaos of zombie hordes made for frustrated and paralyzed survivor teams