Dark Carnival

Dark Carnival is the second campaign of Left 4 Dead 2, that takes place at Whispering Oaks carnival. It starts off on a highway with the Survivors heading towards a Ferris wheel in the distance, passing through a motel complex, and eventually reaching the Whispering Oaks carnival. It is the third Left 4 Dead 2 campaign to be announced by Valve.

Trivia

 * Dark Carnival is similar to the comedy-horror film Zombieland, where the climax takes place in a carnival, and the zombies are alerted by rides being turned on.
 * It may also be a reference to House of the Dead: OVERKILL, in which the protagonists had to shoot their way out of an infected carnival.
 * It is also possible (however unlikely) that the name is a reference to the rap band Insane Clown Posse who often rap about the Dark Carnival.
 * Dark Carnival is host to a new Uncommon Common Infected, the Clown Infected, whose unusual ability is to attract nearby Infected with his squeaky shoes.
 * There also appear to be Infected with T-shirts that read "STAFF", implying they were working at Whispering Oaks when the Infection struck.
 * Dark Carnival's poster is the first poster to feature an infected, as well as the first to be in landscape position, as opposed to every other campaign poster.
 * Coach's and Ellis' clothes have changed in design yet again.
 * The infamous Gnome from Half Life 2: Episode Two makes an appearance in the poster, just between Ellis' legs. It appears to serve the same purpose, as an achievement and unlocks an avatar reward requires the gnome to be won from one of the mini games in the carnival.
 * The tagline in this campaign obviously refers to the height check carnival operators perform on people to make sure they can ride on certain attractions safely. This tagline may have been influenced by suggestions made on the official forums.
 * In the dialogue before the campaign, it reveals that it was Ellis' idea to go on to the highway, and Coach used to go to Whispering Oaks as a kid. It is later revealed that Ellis and Coach really liked the place when they were young during the campaign, because as you go through areas, they will talk about the carnival.
 * This is the campaign used when Valve revealed Scavenge Mode.
 * Dark Carnival's finale seems to be one of the strangest - it takes place at a big stadium where a famous band was about to have a concert. Survivors have to set off the fireworks and/or say something in the microphone to attract a helicopter.
 * Dark Carnival's music.
 * While loading the campaign, you can see the edge of a corner of the poster for Blood Harvest on the right that has been covered up by the Dark Carnival poster. On the left is a band poster for the Midnight Riders.
 * Within one of the hotel rooms from the highway chapter, a younger girl can be found dead. She wears a pair of pajamas with striped socks and is slightly smaller than the others. This is possibly the first instance where a younger person, most likely in their early teens is seen in the game.
 * One of the carnival's mascots, "Moustachio," makes an appearance in a select few mini-games. If the player scores a high enough score, they will unlock an achievement. Additionally, the shooting gallery mini-game unlocks Gnome Chompski, which is the gnome from Half Life 2: Episode Two.
 * Moustachio is the star of two achievements, both of which are found in stage 4: The Barns. First, as soon as you leave the safe house, you will see a test-your-strength game. Take adrenaline and melee the game's lever. The weight will fly out of the machine, netting you the Gong Show achievement. Warning, doing this causes a Panic Event.
 * Next, go a little further through. You should see a whack-a-mole type game called "Stache Whacker". Activate it. Shoot the Moustachios as they pop out. You can keep pressing continue. Once you hit 42, the machine shorts out and spits tickets at you. You've won! You get the achievement Stache Whacker. Warning, this also causes a Panic Event.
 * The helicopter pilot that picks you up has the same model as the helicopter pilot in the original Left 4 Dead, and ends in a similar fate.
 * Whispering Oaks is said to be in Griffin, Georgia, according to the Midnight Rider's website.
 * In all the chapters except for the first and last chapter, the music that plays during horde attacks is a spooky theremin tune.
 * The Blood Harvest Poster can be seen behind the Dark Carnival Poster on Ellis' left.