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.

However, there are more differences compared to Left 4 Dead. There are much more items such as Adrenaline shots, Bile bombs, varied weapons and weapon upgrades. However, the team does have to face more Infected, such as Uncommon Infected and more Special Infected.

There is also a variant of Survival Mode, a mutation called Versus Survival. It has the same format as Survival Mode but this time the Special Infected are human rather then AI-controlled.

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 time to time in order to get more items, ammo and avoid the Tank. 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 (in Left 4 Dead), the melee fatigue cooldown applies.

It is always best to hole up by gathering as much resources and finding the best spot possible before setting off the Horde. For example, preparing special ammo boxes and placing Gas Cans/Propane Tanks in a secure spot can allow the team to grab it quickly in the event of a Tank attack if they do not have any Molotovs on hand.

Once the horde is alerted, the Director will send groups of Common Infected (Uncommons will appear if they can be found in that level; for example, all Hard Rain survival maps will have Worker Infected, while something like The Atrium will not have CEDA Worker Infected because they are not found at all in that level. The Director will then start sending Tanks at the player starting from the 40 second timer. If the Director is feeling merciful, it may give "grace" periods where only normal Infected will be sent.

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

 * The Waterfront
 * Bus Depot
 * Bridge

The Sacrifice

 * Traincar
 * Port Finale

No Mercy

 * The Generator Room
 * The Roof Top

Achievements

 * 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. Be careful when setting up ammo boxes as they will grab them regardless if they have just picked the other one you had laid down even if in full ammo.
 * 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 Infected manage to kill someone.
 * Have a Molotov in handy to deal with the Tanks, especially when the Director sends two of them coming at you. Bile Bombs and Pipe Bombs are also useful for getting the Common Infected away from you.
 * Within 9-10 minutes after starting the clock, one can expect around eight or nine Tanks to be defeated. Tanks usually spawn in tandem with horde attacks, so be extremely careful to not get slowed down by the Common Infected when a Tank is chasing you.
 * Always try to find a spot where it has the advantages you need there. Try to prevent Infected from attacking more than two ways, and make sure you have an escape route planned if you get overwhelmed.
 * Survival mode has similar effects to Versus mode. Jockeys and Hunters can stumble nearby players at the target, and may cause them to fall off causing someone to get them back up. However, a Smoker's drag does not cause damage to players.