Left 4 Dead 2 Review

The laser sights aren't the best thing in Left 4 Dead 2. When you first encounter them halfway through the opening campaign, Dead Center, they're not even the best thing in that room - the man who wants you to go across the road and get him some Cola is. But they are symbolic of a broader change to a game that looked to some like a cash-in: whereas Left 4 Dead was about getting people to co-operate, and a nervous Valve was reluctant to complicate things in case people misunderstood, Left 4 Dead 2 is about making the most of the fact people did get it, by having some fun with the concept. Because people really, really did get it.

On the off chance you didn't play the original, Left 4 Dead 2 is a first-person shooter designed for four players to play together. You pick from one of four characters, choose a campaign and then work with one another to survive the zombie apocalypse the game unloads between the starting point and the last chopper out of town.

The first game was a ballache for Valve to produce, but the results were simple for players to understand, because it had good rules and well-worked systems. On a basic level, you chose a big gun and a pistol and fought zombies until you got to the next safe-room, and then pressed a button at the end and defended against waves of enemies until help arrived. Behind the scenes though, Valve did a lot of heavy lifting. An "AI director" varied the volume and location of enemies depending on your skill, teamwork and previous experiences, and the level design kept you on the back foot with no idea where the next threat would come from, even while it simultaneously left you in no doubt where to go next.

Scavenge mode borrows locations from the main game. This is the swimming pool you fill with zombies in Dark Carnival.

It did almost everything extremely well. Along with hordes of fast-moving "common infected", there were five types of "special infected" the director could deploy to mix things up, and it did. Everyone's favourite was the Witch, a terrifying vision in granny pants, who sat on the floor crying and would incapacitate you if you got in her face, deliberately or otherwise, meaning someone would have to waste time reviving you, probably while other zombies attacked.

All wonderful. Even so, the game felt like an unlikely success. It was a pure co-op shooter where you didn't even have to unlock campaigns or play them in order, and conventional wisdom said you could only do this sort of thing in games if it wasn't the main event. Left 4 Dead proved otherwise, so Valve has kicked off the stabilisers.

Those already expecting new, high-contrast locations and graphical themes wrapped around refined gameplay may still be shocked by the bold changes to the structure of the five campaigns we get this time. Dead Center sets the tone, with an escape from a burning building, a rush to re-supply an entrenched caffeine addict, and a finale that is still built around a siege like the ones in the first game, but which requires you to gather petrol cans to fuel a car rather than simply surviving waves of attack.

The others go further. Hard Rain sees you fighting through a town one way and then fighting back through the same locations as a violent thunderstorm floods them. There are set-piece sections, like a sugar mill where Witches - who wander around in daylight rather than sitting down so you can avoid them - are gathered in numbers and the sun hangs low in the sky, often blinding you to their movements. The Parish, set in New Orleans, takes place completely during the day, and ends with the survivors fighting their way across a huge suspension bridge piled up with abandoned vehicles and disfigured by military airstrikes.

The decision to set much of Left 4 Dead 2 during the day is a big change (and a big challenge for Valve, because it's a lot easier to show people the way forward in the dark - you just strike a light), but my favourite campaign takes place in late evening. According to the developers, Dark Carnival went through numerous iterations before it made the cut, and the work has paid off, particularly in a chase up and around a wooden rollercoaster circuit, and in the pyrotechnic finale. There's more love here than almost anywhere else, especially in the Achievement-focused silliness involving the peanut man, his nemesis Moustachio and Gnome Chompski.

Were Left 4 Dead 2 merely Left 4 Dead set in these locations, it would still be worth playing, but it would also justify claims made by some of the first game's hardcore fans that the only reason there's a sequel rather than more downloadable content is the developer's bottom line. The fact that it's so much more than that almost makes you wonder how Valve got people so upset in the first place. All this stuff!

The new uncommon common infected are memorable and crafty. The clown often leads a train of commons to your location.

Like all the best things in the first game, the new stuff sounds simple but resonates across the whole. There are melee weapons, for example - swords, bats, bars, frying pans and even a chainsaw - and they're immediately crowd-pleasing, tearing up the infected like there's no tomorrow (although I suppose in an apocalypse there isn't) thanks to the improved limb loss. But they also solve a key problem with the first game, which was that you got frustrated when swamped by enemies, because you were only able to shove enemies away and attempt to shoot them once free. Now you can carve them up, and a melee weapon is often taken in preference to a pistol when the opportunity arises. Of course, this new close-quarters competency is carefully balanced so you don't gain too much of an advantage.

There are also three new special infected. Each has a specific role, and they interact with one other in maddeningly clever ways. The Spitter lays down intensely damaging green flob to burn away your health, while the Charger drags one of you away from the group at speed and then slams him or her up and down on the ground until help arrives. The new favourite though is the Jockey, a Gollum-like scamperer who clambers on a survivor's back and steers them into danger - perhaps into Spitter flob, or off a building. Hopefully Valve's merchandise department is already working on Jockey backpacks to replace our worn-out headcrab hats and Companion Cubes.

Elsewhere, specials and regular infected alike receive a boost in the new Realism mode, where people who played the original regularly will discover a distinctive new challenge. It removes various gameplay crutches, like the blue outlines showing you players' relative locations when they're outside your line of sight, and the halos around pickups. Meanwhile, zombies take a lot more ammo to go down unless you aim for the head. It's a different kind of difficulty level to the ones we're used to; rather than simply throwing more enemies at the survivors, it forces you to communicate with fellow players and pay attention to your surroundings to succeed.

Away from the co-op campaigns, Valve improves the competitive Versus mode, where four survivors play against four players alternating between special infected types. There's the long-awaited addition of four-versus-four matchmaking, and if you're playing as infected the heads-up display now shows you your team-mates' cooldown timers (both features are available for L4D1 in a patch, too). The new specials fit in perfectly, and do a better job of encouraging teamplay with their complementary attacks.

There's still no answer for people who want to be able to practice as specials before playing competitively, but there is a new mode called Scavenge, where survivors gather fuel cans to a generator to try and extend each round. A team of specials tries to stop them, and roles are then reversed. Unlike the throwaway Survival mode, where the idea is to survive as long as possible in a certain area, this one has real legs, which you'll probably still be shooting off one another in a few months' time. After its first multiplayer shooter was criticised for being too short, it's as though Valve chose to respond by, er, adding a multiplayer mode.

All good then? Not entirely. With the addition of Realism mode for people who want to be really challenged, there's an argument that the co-op campaign could be a bit more forgiving with respawn rooms and rules. It's funny when the whole team is killed off in classic Left 4 Dead style - perhaps three people are down and the last remaining guy is racing for the boat before a Charger runs him off the jetty - but the novelty of losing 10 minutes' progress is wearing off.

Did I mention I love Dark Carnival? There's a slide.

It wears particularly thin in a couple of areas - most notably the escalator-heavy mall section of Dead Center, and the planks-in-the-water bits of Swamp Fever - when Valve's famous ability to move you intuitively through the world falls a bit short and you end up getting spun around and lost. It won't be a problem when you learn your way through, but wasn't the point that you weren't supposed to have to?

Then again it feels a bit silly moaning about something that's otherwise so excellent, and you're never more than a few feet away from another joke, or gadget, or smart little gimmick that restores the smile to your face. The new characters, for example, like southerner Ellis and his comedy anecdotes, always cut short by the sweary but avuncular Coach, who also has the best situational dialogue: "S***, I need to heal my ass!" "Re-goddamn-loading!" Or the 7/11 store, Save 4 Less.

Or the new adrenaline shot, which temporarily speeds up your actions. Or the defibrillator, which can bring a dead team-mate back to life but occupies a med-pack slot for whoever carries it. Or the "uncommon common" infected - riot cops who only go down when shot in the back, or clowns whose noses you can honk. Or the Achievements, half of which must have been invented to fit the jokey labels, like "Septic Tank". Or the writing on the safe-room walls. Or the grenade launcher. Or the incendiary bullets. Or the Midnight Riders.