
While zombie games aren't new fare (the first Resident Evil is nearly 13 years old), recent technology has made it possible to properly recreate full-on uprisings on our console screens. The recent influx of zombie movies and shows in the past few years - Shaun of the Dead, Dead Set, the Resi movies and even Romero's new (if slightly disappointing) Dead films - have also helped to bring the genre into the mainstream.
Most games, even the recent ones like Dead Rising, have tended to go with the solitary hero role, with one man or woman taking on the un-dead by themselves, occasionally stopping to babysit or chat with an ally. Left 4 Dead finally takes the group survival element, something that is a key part of most films in the genre, and places it into one rather special game.

Powered by Valve's Source engine (Half-Life 2), Left 4 Dead puts you in the role of one of four survivors. There's Bill (the grizzled Army Veteran), Francis (the tough guy biker), Louis (the office worker), and Zoey (the good-looking girl who's handy with a weapon). It doesn't make much difference which character you choose, but simply having the choice is nice enough. Across four scenarios, which can be attempted in any order, your chosen survivor and the others will need to make it past the hordes of flesh-eating monsters, and earn a safe rescue.
Each scenario is split into five levels, and covers a general location-based theme. No Mercy sees you battling to reach a hospital, Death Toll gets your team fighting across the wrecked highways, Dead Air is an epic struggle through an airport, and Blood Harvest takes you out into the dangerous woods. After moving between safe rooms for the first four levels, level 5 ends with a mass battle while you await the arrival of rescue. The scenarios are presented in a movie style, showing a poster on the initial loading screen, and ending with a credit roll of cast and stats, which informs you how many zombies "died during the making of this film".

Part of the title's real beauty comes from its unique AI system, which ensures that no two games will ever be exactly the same. While the actual level layout doesn't change, where the zombies come from and when they come changes each time. Even if you die and have to restart a level, there will be changes next time. There are certain set-pieces too, where you have to perform an action that will summon a horde of un-dead creatures to your location.