Gameplay Modes

There are currently 4 Gameplay Modes in Left 4 Dead, and 8 Gameplay Modes in Left 4 Dead 2.

Campaign

 * Play through a co-operative campaign online.
 * Available in Left 4 Dead and Left 4 Dead 2

During Campaign, also known as Co-op, up to four players work together to try to reach the end of the campaign by fighting their way past large numbers of AI-controlled Infected. There are four difficulty levels: Easy, Normal, Advanced and Expert. Each chapter ends in a Safe Room, a checkpoint triggered when all living Survivors, once inside, close the door behind them.

In Campaign mode, one or more players play as the Survivors, with the rest of the four filled in with AI-controlled "Bots". The Survivors play through each chapter, making their way from safe room to safe room. The last stage in each campaign has an expanded ending called the Finale, which usually ends with players escaping on Rescue Vehicles like boats, helicopters, etc.

Single Player

 * Play a single player offline game with computer-controlled teammates.
 * Available in Left 4 Dead and Left 4 Dead 2

Single Player is a gameplay mode with only one player controlled character. The player assumes control of one of the Survivors, and all the other characters are AI controlled. No other player can join a Single Player game, unless locally (LAN), via the connect "host local ip" console command. Other than that, the same rules as Campaign apply here, except for in Dead Center, or The Passing where you only have to get 8 Gas cans in Solo Dead Center (13 in standard Campaign mode) and 10 in Solo The Passing (16 in standard Campaign mode).

Single Player is the only mode which can be played with Steam set to offline.

This is also the only mode that allows you to fully pause the game (by bringing up the menu).

Split Screen
In Split Screen, two players on the same console take control over two Survivors, and the screen is split vertically, although it can be changed to horizontal in the options menu. The two players can also play online while using split screen.

This game mode is normally exclusive to the Xbox 360 version of Left 4 Dead and Left 4 Dead 2, but may be accessed in the PC versions if you have a controller for the second player and modify some files. Here is a guide to how to play splitscreen on the PC. Plugging the Xbox controller in and out during the loading screen is NOT the only way to set the Xbox controller to player 2. During gameplay, you can also unplug and plug the Xbox controller back in within one second to set the controller to player 2. In fact, the second method proves to be more effective with several people. On Left 4 Dead and Left 4 Dead 2, only one of the two players playing splitscreen on one Xbox 360 console while online has to have an Xbox Live account with gold membership; the other player can sign in as a "Guest".

Survival

 * Play Survival mode and hold out for as long as you can.
 * Available in Left 4 Dead and Left 4 Dead 2

Survival was released in the "Survival Pack," which came out on April 21st, 2009. The point of Survival Mode is to hold out for the longest time, with times being saved and virtual medals being awarded for surviving for certain amounts of time. Left 4 Dead features sixteen maps, fifteen of which are taken from existing campaign levels, and one new map which has been called The Last Stand. The campaign levels have been edited to remove things such as closets and other small choke points often exploited by the Survivors in crescendo events and finales. Survival can be played in Single Player with Console commands or by starting a lobby on your own on Xbox.

In Left 4 Dead 2, Survival Mode is back, this time included with the release of the game. The point is still the same, and the maps are still converted crescendo events apart from The Motel from Dark Carnival's The Highway and The Sugar Mill from Hard Rain's map by the same name, among others. Single-Player Survival mode (with bot allies) is easily accessible this time.

Versus

 * Play as the Survivors or the Infected in an online Versus Mode game.
 * Available in Left 4 Dead and Left 4 Dead 2

Versus is the basic competitive mode for the Left 4 Dead series: two separate teams of four players take turns playing as the Survivors and the Infected competing for the most points. In Left 4 Dead, points are only awarded to teams playing as the Survivors. Points are calculated by the amount of health left in each player and how far the team got. In Left 4 Dead 2, points are still only awarded to the Survivors but no longer use the amount of health left in each Survivor in the score. Instead, points are awarded solely on how far each Survivor got before they died and if they made it to the safe room alive. The points possible for each chapter is the same for both teams. Should both teams make it to the safe room without casualties and without the use of a defibrillator, then the Tie Breaker calculates how much damage each team did to the opposing team, awarding 25 points to the winner.

Before a game starts, the lobby leader chooses a specific campaign to play and the players can choose which team to play on by choosing whether to start as the Infected or the Survivors. For help as Infected or Survivors, review some tactics.

Versus can be done without the need of Xbox Live, but you must have 2 players to do this.

Realism Versus

 * You can't see each other, but they can see you.
 * Available in Left 4 Dead 2

Realism Versus is a game mode that combines Versus and Realism. It was the first Mutation to be released for Left 4 Dead 2, but, due to positive feedback from the community, was made an official game mode as of May 21st, 2010.

Realism Versus follows the normal rules of Versus mode in terms of gameplay style and scoring, but makes things harder for the Survivors as they are bound to Realism rules, such as a lack of Survivor glows and the Witch being able to instantly kill Survivors. Though Realism Versus will appear in the main menu, you cannot play it unless you have downloaded The Passing.

Realism

 * In a REAL apocalypse, good teamwork is all you'll have left.
 * Available in Left 4 Dead 2
 * Main Article: Realism

Realism can be played on any difficulty setting. This mode removes the Survivor auras usually shown around players through walls. Also, halos for items or weapons only appear if you are close enough to do their action (such as grabbing a weapon or pressing a switch). Realism mode also includes a damage penalty for body shots. Rescue closets are removed, making the defibrillator the only way to revive dead Survivors until you reach the safe house, where they will respawn for the next round. Witches kill instantly on any difficulty except Easy and no longer receive bonus damage from point-blank shotgun blasts, making cr0wning impossible. Speech bubbles over the Survivors are disabled when speaking via the microphone, although the speech bubble still appears above the character's icon. Overall, this gameplay mode was created to take the teamwork factor that made the Left 4 Dead series famous to the next level. Realism can also be played by creating your own lobby.

Scavenge

 * Play as the Survivors or the Infected in a round-based competitive match.
 * Available in Left 4 Dead 2

Scavenge is a competitive gameplay mode in Left 4 Dead 2. It is a round based gamemode in which Survivors have a limited amount of time to find up to 21 gas cans to fuel up a generator (or car), while fighting against player-controlled Special Infected much like in a Versus game. Games can consist of one, three, or five rounds total, though not all of them may be played. After all the Survivors are incapacitated, the time runs out, or the Survivors collect all of the gas cans, the teams switch sides. Whichever team collects the most gas cans in a single round wins that round. If both teams collect the same number of gas cans, the team that collected them the fastest wins that round. When one of the teams wins either one, two, or three rounds (if there are one, three, or five rounds total, respectively), that team wins the match.

Scavenge can also be played without Xbox Live, but this requires 1 player as the Survivor and 1 player as the Infected.

Mutations

 * Available in Left 4 Dead 2

Mutations are tweaks and changes to the normal game rules. They can be for any game mode, which will be introduced each week by Valve on the in-game blog. Details for the next Mutation are revealed on at the same time the Mutation is released on Friday, via the blogs. On regular intervals Valve initiates a "Favorite Mutation" survey, and winners are put back into the cycle.

The first Mutation released, Realism Versus, achieved enough positive feedback from the community that it was turned into a permanent gameplay mode.

To see the order of Mutations released since it was announced, please see the main article. Mutation need Xbox Live in order to play.