Left 4 Dead has, in the year since its first announcement, been met with a barrage of pre-emptive plaudits.
From the two hour queues at QuakeCon to play a beta, to the months-long salvo of previews that have had a steady trickle of journalists come away hugely impressed, and mostly with the frustrating confession that "no preview can do this game justice - you simply have to play it."
You can see my dilemma - to make this feature anything less than redundant, it's now my job to try and do the game justice: to run my fingers down your spine, crowbar open your ribcage, straddle your chest, and punch your heart into your half-closed mouth.
I'll try my best, but if you find it difficult to conjure extreme emotions by reading about someone else playing a game, you can recreate the feeling of playing Left 4 Dead by simply writing an email describing how much you hate someone. Leave no aspect of their character unassassinated - really let rip. Then contrive to accidentally send the email to that person.
The dread, palpitations and foul language that will result are identical. If you do this in a room full of people trying to murder you, the illusion will be complete.
Chet Faliszek, the game's writer and one of the funniest parts of the internet since it was all HotBots and AltaVistas, meets me in Valve's furry-strewn foyer.
After a walk around the Left 4 Thanksgiving Valve offices - during which time I trade an alarmed glance with Gabe Newell before burying my face shyly in a plush headcrab - I'm delivered to the playtesting room.
Chet takes his place behind me, and he'll be offering me advice and information as I play through the new rural map, which culminates in a farmhouse stand-off surrounded by cornfields. It's classic, it's clichť, and it's five decent-sized stages away from the temporary campsite I find myself in now.
Like the other maps, each scenario is broken up into five large maps, punctuated by safe areas where you can reload, patch up and see who was letting the team down, in the form of stats, achievements and team betrayals.
The new rural level has an extra layer of creepiness over the urban; it feels more open, and the brick of a city is always going to feel safer than a fading, endless forest. This is particularly true of a forest that generates zombies.
Whereas the city level has a great line in claustrophobia, and keeps you on your toes with vertical combat, the cornfields level is that more fundamentally terrifying thing - a level where there is no safety, nothing to put your back against. It's especially true in the final dash through the cornfield, running nearly blind and just hoping that the zombies won't arrive before you get the doors closed.
You never see them spawn (that would be shit) but they've got the uncanny ability to be suddenly there. For the living dead (pedants please read 'those infected with a horrible disease that turns them into cannibals') they've got a real dramatic flair.
Having been assured so many times that the gameplay was beyond the human capacity for description, my first thought was, this is pretty much what I expected. The four characters - John Everyman, Tattooed Biker, Freshly-Weathered Rich Girl and Grizzled Veteran - are unchanged, and are as much a part of zombie canon as putting too many vowels in the word 'brains'.
They all play identically too, which'll reduce the bitching about who gets to play the cool biker.
The weapons range hasn't been extended, either - a choice of pipe bomb or molotov, SMG or shotgun, and a medkit each. It's certainly not the most expansive set of weapons, even with the auto shotgun, assault rifle and hunting rifle that become available at later checkpoints.
But what did you want: bio-rifles and portal guns? Left 4 Dead keeps a tight focus on what it is; it don't need no stinkin' gadgets.
THE FRIENDLY SOCIETY
Co-op games often let you get away with letting you not play co-operatively. Larger group games all allow solo tacticians to profit from their lone heroics. Left 4 Dead encourages you to work together in the most sensible way possible: by killing anyone stupid enough to get stranded.
Zombies can appear at every available entrance, necessitating someone to cover your back. The Smoker and Hunter have incapacitating attacks, forcing teammates to rescue their friends by getting close and slapping them off.
You can revive fallen mates during their bleed-out time, but doing so incapacitates you for a short while: so should you? That depends: is the area clear? Are you sure? Are you covered by your other two friends? And most importantly, has the clumsy prick been shooting you in the legs?
Left 4 Dead is not easy; viral armageddons so rarely are, as NoŽl Coward might say after a sip of tonic water. But it makes for some great moments of stress, drama, triumph and overwhelming failure. The dash for the safe holes with a gang of infected athletes chasing you down is pure 28 Days Later, and the degree to which that feeling has been recreated in a game without any real script is incredible.
It's all thanks to an awareness and love of modern zombie movies. And having lots of enemies. Take one moment, when a Boomer had vomited on my friend, and the regurgitated pheromones had turned him into a zombie magnet.
He crouched, allowing me to pick off the zombies without puncturing his cheeks, and between us, we killed them. What I hadn't noticed was that a queue of zombies had formed behind me, trying to get to my vomit-sodden chum.
My monitor was completely and suddenly full of zombie. Lunging, ash-grey zombies, as close as they could be to my face without the whole thing feeling erotic.
I'm almost tired of saying and thinking "it's like a bloody movie" - I don't think I've heard anyone saying "it's like a movie" about something that so obviously isn't a movie since 9/11 - but this is possibly what people have been struggling to get across; the reason people are saying you have to play it to feel it.
Because The Director manipulates your emotions to the point where you're glad to stop playing, open the curtains and rest your dilated pupils. But the options play through your mind, the missed opportunities, the room for improvement. And you want to play another game right away.
THE DIRECTOR'S CHAIR
Have I introduced you to The Director? You've possibly heard about him; he's the playful AI mastermind that'll be toying with your adrenaline levels. Given that zombie hordes don't have much intelligence to draw on - uncuddly noggin chompers that they are - the cleverness lies in their deployment, which is governed by The Director.
No area is safe, and no area is a guaranteed carnage bomb, so you can never be sure around which corner, or from which patch of forest the hordes will come. Instead of scripted moments, the game decides what to do based on preceding events, so you'll end up forced to trust your sense of dramatic timing, rather than map memory.
If you've just had a prolonged onslaught of hell's overspill, then The Director will loosen the thumbscrews, and give you some dramatic respite.
If that sounds generous, it's not. Your nervous system may have briefly jammed Left 4 Dead's shredding machine, but the machine's still plugged in. Once The Director reckons you've had time to calm down, on they come.