In your first stand you get to set off a huge cannon attached to a military vehicle to clear your path, and from there it's just rinse, wash, and repeat. Your last stand before completion is turning on a power generator to get the Dawn of the Dead-esque bus off the auto lift. The only moment that's just a bit different is when the power goes out. If you're not near the generator, you actually have to fight your way through the masses of undead flesh to get back and switch it on. (Do it fast enough and you get an achievement.) Left 4 Dead 2 promises to make us work to stop the horde, and I hope Valve follows through on that promise. Don't get me wrong – I love to empty clips into zombies – but after playing for hundreds of hours it can get a little old.

In closing, "Crash Course" is a solid and fun offering to help you pick up the game if it's starting to feel a little stale. However, it's a short-lived run and takes a cut of your MS points for Xbox owners. If you don't mind paying the points, though, I totally recommend that you download this. For PC gamers... what are you waiting for? GET IT!

Because Left 4 Dead is so centrally focused on four-player co-op, you'll need to coordinate to get the best of the ever-changing AI. Far from just another mindless shooter, L4D encourages you to stick close to your team, patch each other up when wounded, and cover all of the angles when someone mistakenly sets off a car alarm, thus summoning a stunning amount of enemies. Ideally, each play-through is completely different from the last, but you'll start to notice familiar patterns as you continue to complete the nearly story-free missions. For example, upgraded weapons appear in spot A or spot B, and the Tank spikes intensify once you cross a certain threshold. Nevertheless, there's enough variety to add longevity to the experience with the mixing up of enemy spawn points, grenade locations and med-pack cabinets.

If you find yourself exhausted from surviving as the four endearing characters – Bill the grumpy war-vet, Louis the nervous nerd, Zoey the fearless college kid, and Francis the vitriolic biker – you can switch gears to competitive multiplayer in Versus. With two teams of four, your squad alternates between Survivors and Infected, giving you control over the aforementioned special zombies as you try to foil your opponents' escape. The Infected team requires precision cooperation, perhaps more so than the rifle/shotgun/machine-gun toting humans, as you're quite vulnerable as a zombie. Lengthy respawn times might turn some away from the mode, and impatient people will find themselves staring at that countdown a lot if they're not willing to wait for the perfect opportunity to strike. Acting alone will earn you a shotgun blast to the face, so cooperation is crucial.

Sadly, only two of the four possible campaigns are available in Versus. The multiplayer mode adds excellent legs to a shooter that you might otherwise tire of after a couple completions, but after extended play you'll certainly start to become bored of looping the same stages. Even so, it is without a doubt addictive and fun to blast your way to the next safe house as you flee from the horde, protect your friends, avoid the lethal one-hit-kill "Witch," and make smart use of multiple tactics. L4D slowly becomes more formulaic than frenetic, which doesn't play well in to the themes of the game. Moments that previously haunted you, such as rooms filled with shredded corpses, eerily silent sewers, and the trumpeting crescendo that signals an incoming swarm become routine rather than emotionally evocative.

Still, it's impossible to resist the urge to fight off the attacking mass of bloodthirsty Infected in a desperate struggle to survive. More campaigns would definitely have been appreciated, because you'll breeze through the entire game in six to eight hours. Because the AI is constantly changing, if only slightly, every match does manage to feel different. With a breadth of witty character dialogue exchanges to listen to, the dread of death can briefly be alleviated with a whimsical comment or ironic joke, too. And with the addition of Versus multiplayer, you'll have plenty of horror to experience as you strangle, shred and smack human players around. So, it's not for a lack of things to see and do that Left 4 Dead feels slightly limited; it's the limited places to experience these moments that hurts.

Left 4 Dead is a fantastic twist on an established (and played out) theme. With very little story to speak of beyond scribbles on walls, there isn't very much depth to anything but the combat, which is endlessly entertaining regardless of how long you play. It's just a shame that many players will become bored once they've finished the campaigns, especially if they're not into the competitive mode.

For the rest of us, there is no end. Only survival. And we'll contentedly shoot our way to whatever boat, chopper or plane wants to take us to our next terrifying co-op adventure.

great.