Left 4 Dead

Left 4 Dead is a first-person shooter video game made by Valve Corporation for Mac computers, Windows PCs, and the Xbox 360. It was released in North America and Australasia on October 18, 2008, and on October 21, 2008 in Japan and Europe. There are four game modes available: a single-player mode, where the player controls one character and the 3 other characters are controlled by the game; a four-player, co-op campaign mode; an eight-player online versus mode (4 humans and 4 mutated zombies/"Special Infected"); and a four-player survival mode. Left 4 Dead was named the Best Multiplayer Game of 2008 by IGN, GameSpy, BAFTA, Spike TV, and NoFrag. The sequel, Left 4 Dead 2 was released on November 17, 2009. 
Characters.
There are four characters to choose from (gameplay is not affected with character choice): 
Plot.
The Green Flu, a virus that turns victims into rabid zombie-like beings called the Infected, breaks out in the USA. Some Infected mutate into stronger Special Infected. The 4 characters try to reach a rescue vehicle throughout each campaign, except in the final campaign The Sacrifice.