Survival Mode

Survival Mode is a game mode which was released in the Downloadable Content from Valve Corporation; the Survival Pack. This game mode throws waves and waves of the Infected at the Survivors until they die. There is no way to really win this through surviving, but instead the goal is to survive as long as you can and set new records.

There are currently thirty-one different maps to play on in Survival Mode, thirty come almost directly from the campaign mode while a new map called The Lighthouse, which was released with the pack, but appears to be attributed with something called The Last Stand. All of the maps have been modified to essentially trap the Survivors into the designated area. Doors have been blocked off, and most choke points such as closets have been removed, leaving the players out in the open. It is possible that, in the future, more maps will be released for the gametype, perhaps filling out the campaigns in entirety.

Left 4 Dead
Each survival match starts with a setup time, allowing time for you and your team to scour the map for useful items. The teams will find health kits, tier 2 weapons, pipe bombs and molotovs, pills, propane tanks, oxygen tanks, and gas cans scattered around the area. Each Survivor holds on to pills, a health kit and dual pistols at a spawn point of each map(before starting the match), right after loading the Survival game. You can take as much time as you want, as the timer at the top of the screen doesn't begin until someone hits the button that alerts the horde. Once the button (typically in the form of whatever the chapter's Crescendo Event is in the campaign) is activated, the action gets off to a furious start and escalates from there.

Left 4 Dead 2
Survival mode gameplay in Left 4 Dead 2 is very much the same related to Left 4 Dead's survival mode. Differences include being given adrenaline, bile jar, new weapons, and having to deal with a wider variety of different special infected. The key to Survival is to survive endless minutes of the Zombie horde and accompanying them is the Special Infected. Though The Most appearances of the Special Infected is The Tank. On Dark Carnival's Stadium Entrance, you can also have another way to summon the Horde. Also in Left 4 Dead 2, there is a new mutation mode called "Versus Survival" which is a mix of both Survival, and Versus mode. In Versus, the Survivors' objective is the same as the normal Left 4 Dead 2 Survival Mode, with the added difficulty of player-controlled Special Infected. The teams take turns playing as the Survivors, and the goal is to beat the other team's survival time.

Strategy
As always, teamwork and staying together are necessary for survival. Beyond that, survival strategies vary from map to map and from team to team. It is possible to obtain a Gold Medal achievement by staying in one area of a map, but some may find it more advantageous to move from room to room in order to get more items and ammo. Difficulty increases with time as supplies dwindle, and surviving often involves fending off multiple Special Infected and at times, multiple Tanks. As with Versus mode, the melee fatigue cooldown applies. If players are very strong, they can stay together for a long amount of time.

Various Special Infected spawn at first with Common Infected. After 42 seconds in-game, a Tank will spawn and attack. There are "grace" times where you will only be facing Special and Common Infected, without a Tank harassing you as much during the first 42 seconds to 5 minutes.

No Mercy

 * The Generator Room
 * The Gas Station
 * The Hospital
 * The Roof Top

Crash Course

 * The Alleys
 * The Truck Depot

Death Toll

 * The Floodgate
 * The Church
 * The Street
 * The Boat House

Dead Air

 * The Crane
 * The Construction Site
 * The Terminal
 * The Runway

Blood Harvest

 * The Warehouse
 * The Bridge
 * The Farmhouse

The Sacrifice

 * Traincar


 * Port Finale

The Last Stand

 * The Lighthouse

Dead Center

 * Mall Atrium

The Passing

 * The Riverbank
 * The Underground
 * The Port

Dark Carnival

 * Motel
 * The Coaster
 * Stadium Gate
 * Concert

Swamp Fever

 * Gator Town
 * The Shantytown
 * The Plantation

Hard Rain

 * Burger Tank
 * Sugar Mill
 * Mill Escape
 * Town Escape

The Parish

 * Bus Depot
 * Bridge

The Sacrifice

 * Traincar
 * Port Finale

No Mercy

 * The Generator Room
 * The Roof Top

Achievements
thumb|300px|right|Achievementors "Beat the Rush" Guide for Left 4 Dead 2
 * See Main Article: Achievements

Left 4 Dead

None of the Survival Achievements are present in the Xbox 360 version of the game since it is free DLC.

Left 4 Dead 2

Tips and Tricks
These tips are general, not for specific maps.
 * Always stick together; breaking off will cause a large problem to the team and severely weaken them.
 * Try to find everything you can find in the map. Throw Gas cans and Propane tanks in a place where you won't shoot them by accident, but have a backup supply of "Molotovs" if you do not have any Molotovs.
 * Place everything you need in the area you plan to hold out in. This is useful as you do not have to run to a nearby supply area and get attacked easily.
 * Players playing with bots will have a slight disadvantage over a team of players. Bots cannot carry throwables, nor are they good in teamwork. However, the bot's accuracy is better of a players so if needed, a bot can be useful for taking out Smokers and Spitters from a distance.
 * Try to find a melee weapon in the map. This is useful when you are surrounded by Infected or when killing Tanks. Most maps tend to have a couple of melee weapons scattered throughout the area.
 * A Defibrillator will be extremely useful in case the Tanks manage to kill someone.
 * Always try to find a spot where it has the advantages you need there. Try to prevent Infected from attacking more then two ways, and always find a spot where you can leave in an emergency.
 * Survival mode has similar effects to Versus mode. Jockeys and Hunters can stumble Survivors near their target, so try to avoid sticking too close to each other, but not too far from each other.