At other points, Valve uses the scenery to spark off bits of banter between the four survivors. Ellis the redneck mechanic is the clear star in many of these conversations, getting all excited when the group approached a kids play area, and holding court with stories about his idiot friends - including one who drowned in the Tunnel of Love (naturally this tale was told just as we stepped into the ride itself, further adding to the weirdness of the situation). Naturally such touches don't have much effect on gameplay, but they still play a valuable role in contributing to horror flick atmosphere.
Indeed, many of the other additions to this sequel, particularly the new special infected types, feel like they're more evolutionary than revolutionary: they don't radically change anything, but they do give the action some much-needed variety. In addition to the rampant Charger, your new threats include the Spitter, who spits massive globs of corrosive acid, and the Jockey, who climbs aboard your head and tries to steer you into the nearest crowd of Infected. The former didn't prove too difficult to handle, on the easiest difficulty at least, but the latter was both hilarious and highly irritating - obscuring your vision while dragging you deeper into trouble.
The highlight of my playthrough, and indeed the bit that showed the most progress from the last game, arrived with the final showdown at the rock gig. Throughout the level there are posters advertising an upcoming gig for a big metal band, and when you finally arrive at the venue you find the whole place has been kitted out for a concert that never happened. Naturally it would be a shame to let all this hard prep work go to waste, and to attract the rescue chopper you need to start the entertainment systems that were meant to accompany the show.
In essence, the objective here is to survive a lengthy battle in an open, arena-like environment. So far so classic L4D, but there are loads of interesting camp points and toys that can be used to vary your strategic approach to the fight. Two high scaffolding towers rise out of the seating block, and if you climb to the top you'll find that they each hold a super-powered weapon - either a grenade launcher, or a high calibre sniper rifle. You might consider parking the whole team up here, but if you do you'll miss out on all the good stuff on stage - a pile of medikits, bottles of pills, and defibrillator that can be used to revive dead players. Even better, there's a button that fires off a massive set of fireworks; I managed to nail a tank as he was climbing up from the seating block, and the resulting inferno was highly satisfying.
We probably should have gone into battle with a concrete plan, but amid the chaos of a busy preview event, my colleagues and I ended up winging it. To no-one's surprise, the resulting rumble was a total fiasco, but we did manage to survive until the helicopter arrived. At that point my sense of honour totally deserted me, and I abandoned a fallen friend for the sake of a quick rescue. One of the other journalists managed to struggle aboard just in time, but the other two were left to die on their backs amid the frenzied zombies. We got away, but with the sour taste of shame in our mouths. For all the new bells and whistles, it's good to know core Left 4 Dead moral dilemmas remain intact.
Left 4 Dead 2 is scheduled for release on November 20 for PC and Xbox 360.