History Videogame / Left4dead2

** The Chainsaw Massacre mutation amplifies the survivor bot's stupidity to new levels. They will either run ahead or lag badly behind and not do too well in saving you from special infected.

** [=TAAAAAAAAAAAAAAAANNNK!!!=] plays it for fun, by removing AI-controlled special infected and having players only be survivors or Tanks.

* ZergRush: The AI director will send these at you at random, when a boomer vomits on you, in pre-programmed Crescendo Events where you're forced to make a ton of noise to continue moving, or if you accidently set off a car alarm, [[WebAnimation/ZeroPunctuation or whenever he's bored, which is]] ''[[ZeroPunctuation all the time]]''. The normal infected also like to rush pipe bombs because of the smoke detector alarms rigged to them, and Boomer bile (both regular and purified) for obvious reasons.

* ZergRush: The AI director will send these at you at random, when a boomer vomits on you, in pre-programmed Crescendo Events where you're forced to make a ton of noise to continue moving, or if you accidently set off a car alarm, [[ZeroPunctuation or whenever he's bored, which is]] ''[[ZeroPunctuation all the time]]''. The normal infected also like to rush pipe bombs because of the smoke detector alarms rigged to them, and Boomer bile (both regular and purified) for obvious reasons.

[[caption-width-right:330:[[CloudCuckooLander Ell]][[MrFanservice is]], [[TeamDad Coa]][[HandicappedBadass ch]], [[SassyBlackWoman Roch]][[TeamMom elle]] and [[DeadpanSnarker Ni]][[{{Jerkass}} ck.]]]]

*** That said, the military does act rationally, if harshly. At the end of the Pariah they arrange a special helicopter for the 4 survivors because they are presumably carriers. On the other hand, they shoot normal humans who try to get past the barricades without any degree of contact without a second's hesitation.

* [[EveryoneCallsHimBarkeep Everyone Calls Him Coach]]

* ItGotWorse: Leading up from the first game, there is evidence that much of the urban parts of America are completely overrun and that the infected are changing even more; just a month after the first case.

The plot is roughly the same as the last game, a deadly virus epidemic has claimed the country. You play as one of four survivors trying to make their way though bloodthristy horde of mutant infected to reach safety. The difference this time out is the setting is located somewhere around the [[DeepSouth Louisiana area]] and the survivors now being a new group of four.

The game also received massive critical acclaim for its use of emergent narrative- the parts of the story that they don't tell you, and the interactions of the survivors.

* OurZombiesAreDifferent: Of the infected, easily-enraged sort much like in ''[[TwentyEightDaysLater 28 Days Later]]'' and various types of {{Elite Zombie}}s.

The 2009 sequel to ''VideoGame/Left4Dead''

*** The panel is intact in the this game's port, to counter Spitters getting a cheap shot.

* {{Hammerspace}}: If you have a melee weapon and are incapped(or a chainsaw runs out of gas), this is where the pistol comes from.

* PlayerPreferredPattern: Auto shotguns are being the most used weapon, despite the nerf it got in its ammo capacity, but AK-47s are another commonly used weapon due to its power. Its accuracy is mediocre but the gun becomes a powerhouse with a laser sight. Magnums and melee weapons becomes everyone's weapons of choice for realism mode since they're the only weapons that can still kill common infected in one hit.

* BreatherLevel: Although it's definitely not on your side, the AI director does tend to give you a breather in-between swarms of zombies or boss encounters, especially if you're just limping through. The period of time is increasingly brief on higher difficulties.
** The raft in ''Swamp Fever'' and the elevator in ''Dead Center''

* WeCannotGoOnWithoutYou: If there are any bots on the team, you'll have to start the level over again if all the human players are dead, regardless of if there is a bot player alive. It becomes mind-boggling when playing against a team of bot Survivors in versus mode and they are capable of moving through the level on their own without the guidance of a human player.

* UnwinnableByInsanity: in the [[CollectionSidequest scavenge finale]] of The Passing, the AI Director ''can'' spawn boredom hordes and specials if you take too long before talking to the first game's Survivors. If you do, activating the elevator will make the AI director think you have lowered the bridge, and he will begin throwing the infinite tanks and hordes at you... Even though you ''haven't'' lowered the bridge or even collected ''one'' gas can. And the best part? This doesn't reset if (when) you game-over. The only way to avoid it is to 1) quit the campaign and start from the beginning, or 2) ''not take too long before talking to the other Survivors.''

* TheNicknamer: The survivors will refer to each other and the Special Infected by various nicknames over the course of the first campaign (for instance, Rochelle calling Nick "Suit", Nick calling Ellis "Overalls", Coach calling the Charger "one-arm", Nick referring to the Hunter as a "scrawny little bitch I'm gonna kill", etc.). The Tank gets a nickname as well, though [[OhCrap none of the survivors are in the right state of mind to think up one]] when they encounter the first one.

* PaintingTheFourthWall: The ending to the "Dark Carnival" has you activate the stage effects for a band that was originally going to play. The next two Tank cues then have a very distinct rock feel to them over the original orchestral.

The game sports a few new features such as three new special infected (The Charger, the Jockey, and the Spitter). Also introduced in the sequel is the new Scavenge mode, a eight-player mode similar to Versus where the point isn't to reach the safe room; it's to collect gas cans. Also introduced is Realism, where most auras are removed (including the ones around teammates), Witches instantly '''kill''' on any mode except Easy, there are no closets, and a few other things. The narrative to the game has also changed as each campaign now leads into another rather then be stand-alone like the first game did.