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Left 4 Dead puts four human playable or AI-controlled Survivors of an apocalyptic pandemic against hordes of the Infected. Regular Infected are controlled by the game AI, while human players can control up to four mutated Special Infected with special abilities in Versus mode. The goal of Left 4 Dead for the Survivors is to help each other make it through a level to safety. Infected players must cooperate to stop them.

The basic gameplay never changes from map to map, so players will learn their way around fairly quickly. The Director keeps things from getting monotonous, however, by throwing in different challenges in every level. No two playthroughs are exactly alike.

Gameplay

The Survivors
There are four playable human characters in the game. Every Survivor has his or her own unique appearance, personality, and background, though all Survivors are equal in speed, strength, rate of fire and health, etc. There is no "strongest" Survivor, so character choice is purely player preference.

The Infected
In addition to the Common Infected, there are five different types of Special Infected in the game. Only four are usable by players in Versus Mode. Each Infected has its own unique attacks and method of use, but all attempt to work in tandem to defeat the Survivors before they complete the level.

Levels

Each of the 5 campaigns has the player(s) follow a generic path of going from point A to point B with a few different routes and awards stating who took the least damage, etc

.