Valve, in a move that has probably led to some begrudging Half-Life fans, have released a sequel to one of their games a year after the original was launched. So welcome to Left 4 Dead 2, I can't say that you'll be receiving much in the way of good ol' Southern hospitality in Savannah, but there's plenty of companionship: some living, but mostly dead.

Another group has replaced our four champions from the original game; your new playmates are Rochelle, Ellis, Coach and Nick. As with the survivors of the first, the new characters appear to be immune from the End of Days-inducing zombie pandemic that has gripped the United States (if not the whole world). By playing through the offline or online Campaign modes in order, you have the opportunity to see the survivor's story unfold, more so than in the first game.

New survivors, new monsters, same apocalypse

It's not just new characters and locations that await you in the sequel. For those lucky enough to have an Xbox Live Gold subscription, or are playing on Steam, there are two new online play modes as well: Realism mode and Scavenger mode. Realism mode, sees you play through a campaign with many of the helpful in-game features—such as highlighting where allies and equipment are—turned off. A campaign in Realism mode with the difficulty set to Expert will be as difficult as a campaign play through can get (and the requirements for one of the achievements).

Scavenger mode builds on the fuelling system in the finale of the Dead Center campaign. Here, two teams take it turns to play as survivors or infected: survivors desperately try to fuel a generator, while the infected do their best to stop them from achieving this goal. The team that fuels up the generator the most wins the round, and the team that wins the most rounds wins overall.

Scavenger mode is sure to fuel plenty of online excitement

New features in L4D2 include the introduction of a selection of melee weapons that you may equip rather than a pistol, or pistols, as a side arm or you could have a magnum instead. The variety in ammo consuming weapons has increased, so has what you can throw at the infected masses and what's available for you to keep your character alive with.