Survival Mode

Survival Mode is a new mode which was released in the new Downloadable Content from Valve Corporation; the Survival Pack. This gametype 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 eighteen different maps to play on in Survival Mode, seventeen 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.

Gameplay
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 four health kits, tier 2 weapons, pipe bombs and molotovs, pills, propane tanks, oxygen tanks, and gas cans scattered around the area. 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.

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.

No Mercy

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

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

Crash Course

 * The Alleys
 * The Truck Depot

The Last Stand

 * The Lighthouse

Dead Center

 * Mall Atrium

Dark Carnival

 * The Motel
 * Stadium Gate
 * The Concert

Swamp Fever

 * Gator Farm
 * The Plantation

Hard Rain

 * Burger Tank
 * Sugar Mill

The Parish

 * Bus Depot
 * The Bridge (Left 4 Dead 2)



Achievements
There are 7 Survival Mode achievements in Left 4 Dead and 1 Survival Mode achievement in Left 4 Dead 2.

Tips and Tricks
These tips are general, not for specific maps.


 * Stick together - Many times people become headstrong and run away from the pack. This dooms the person who runs away and weakens the group of survivors.
 * Dig In - Staying in one location, usually around an ammo location, makes replacing spent weapons easier.
 * Use the buddy system - When going for ammo always take a partner, this way your back is always covered.
 * Flank the Tank - When you hear the tank music rise above the horde, switch your focus to the tank. Many people instinctively backpedal and shoot, and this only leads to getting backed into a corner.  Try to get your team around the tank. (For Left 4 Dead 2: When the tank is pummeling a survivor, getting behind it and hitting it with the melee weapon deals out a lot of damage and saves ammo)

THESE TIPS ARE STRICTLY FOR LEFT 4 DEAD 2
 * Grenade Launcher - Utilize the grenade launcher early for maximum effectiveness (In my test, my team showed a 4 minute increase in survival time when using the grenade launcher first)
 * Adrenaline - When preparing for the game, do not take the adrenaline instead of pills. Adrenaline doesn't last as long, or restore as much health.
 * Weapon Hording - If you have discovered this trick you know that it doesn't work. You can move weapons to certain locations depending on what weapons are already there. (e.g. switching an M16 for the Chrome Shotgun drops the M16 by the shotgun spawn point)  This seemed like a good idea until it was play tested.  When the rush is started, all the weapons that were horded disappear and don't respawn.