When the zombie apocalypse comes, and trust us it will, you can learn a lot from studying Valve\'s new instructional video game, Left 4 Dead 2.

Deep South hunting

Left 4 Dead 2 (L4D2) is the follow up to the hugely popular Left 4 Dead which demonstrated the basics of teamwork when struggling through hordes of the undead. The second ups the stakes in a number of ways and once again finds four survivors left marooned in what feels like an ocean of zombies. Players make their way through the American Deep South to find salvation, traversing malls, carnivals, desolate factories and roads populated with abandoned vehicles, either killing zombies or getting killed. In L4D2’s case killing means slashing, blasting, gunning, striking or chain-sawing your way through what feels like never-ending armies of infected undead. The hordes aren\'t your classic zombies either- they can sprint like Usain Bolt, and have a nasty tendency to mutate. Cue for example new special infected zombies like the Spitter, with its terrible acid-reflux, or the aptly titled Jockey that rides you like a Durban July filly.

Teamwork

Just like the first game, L4D2 needs to be experienced online to truly appreciate it. That’s not to say single player mode is useless. Your three team mates can hold their own shooting and will heal you when you’ve been clawed, but they are particularly reluctant to throw Molotovs or move into proper defensive positions. This is of course why playing online is such a blast. Find the correct players online and your team will be mowing down zombies like it’s grass cutting day at Wembley Stadium. Playing online in the Versus mode you can also spawn as special infected zombies, using their abilities to kill the survivors. A new edition to the series is Realism Mode in Versus which turns off the halo surrounding players so you can’t see them behind a wall, significantly upping the importance of communication in game. The hectic short-play Scavenge is also new and it pits four survivors against four zombies in a battle to find fuel.

You won’t be disappointed upgrading to L4D2 since it improves on the first one in a number of ways. And, if you haven’t played Left 4 Dead yet, welcome to the best zombie slaughtering title around.