This preview is arriving twenty minutes late, because the rigid demo schedule for Modern Warfare 2 was thrown into chaos earlier today when Verne Troyer arrived unexpectedly and was granted an extensive private screening. In this way, at least, Modern Warfare is the Mini-Me of E3: a bona fide showstopper. Every mention of it in the aisles and display areas of the LA Convention Centre is followed by a deferential pause, and other games - even fairly important ones - are often found struggling to get out of its way. Everyone feels a little nervous in the presence of real success, and Infinity Ward's game managed to be one of the genuine stars of a Microsoft press briefing that also included appearances by The Beatles, Steven Spielberg and a hard-coded science-bending Pinocchio.
It might have been safe by now to trade on reputation alone, but Modern Warfare 2's demo has the elegance, intelligence and poise - not to mention the sense of streamlined chaos - that only comes from hard work. Its snowy mountaintops and blizzard-swept bases dazzle at 1080p and 60fps, but an extended preview behind closed doors suggests that the real standout element is the way Infinity Ward's game tugs you along as it slips invisibly from one encounter to the next, varying the approach, restacking the odds, and changing the rules so confidently you hardly notice it.
We start with a touch of isolated spectacle, perched on an ice ledge high above a snowy ravine, on a mission to infiltrate an enemy installation. Our guide is Captain MacTavish, gruff and experienced, his days of taking orders from somebody called Gaz and suffering under strange nicknames long behind him. He's the teacher now, and the player is, once again, cast in the role of eternal student, but what follows is no simple replay of the last game's irradiated saunter through Prypiat.
Climbing an ice wall to the base above is a chance to study the finer detailing, as tiny cracks skitter outwards from the strikes of your picks, frost gathers in MacTavish's beard and the wind whips constantly at the cuffs of your coat. It's also an opportunity for the developer to indulge in a little light scripting, with sudden jet flybys dislodging ice and stone from above, and a daredevil leap that ends up with a - predictable, yet no less effective - last-second rescue.
From there, with the mountain behind you, Infinity Ward offers an unhurried lesson in stealth, as you calmly headshot your way through the outskirts of a base, with a persistent drip-feed of advice and encouragement from your mentor and no need for gauges to tell you how visible you are or alarms to alert you if you're spotted. Once inside the base, a blizzard descends, and you're free to move through the low visibility cloud, taking people out - or fatally stumbling into them - from much closer up.