It started with a nuke.
Except, if you ask me, that's a popular misconception. The nuclear weapon that goes off in Call of Duty 4: Modern Warfare may have been the smoking gun that drove us toward things like Modern Warfare 2's infamous terrorist siege in a Russian airport, but the shock and awe at the heart of Infinity Ward's single-player campaigns began longer ago than that. Perhaps it was in September 1942, during Call of Duty 2's Russian campaign, when your commander told you there weren't enough weapons to go around and you should wait for the man next to you to die, then use his.
So it shouldn't be surprising that while other action threequels struggle to manage expectations set by simply Making Everything Bigger last time around, Modern Warfare 3's campaign still knows how to make an impact.
Images of smoking skyscrapers in Manhattan and London Underground carriages burning in the dark may be blunt instruments in some respects ("respect" not being a word I expected to feature in this paragraph, for what it's worth), but plunged into their proper context they provoke a variety of responses. A giant worm, meanwhile, provokes just one: "A giant worm!" And where do you go from there?
The Call of Duty formula certainly works, then - probably not the big most exciting revelation on this page - but for the likes of Sgt "Frost" Westbrook, part of a Seal team swimming around somewhere in the waters off Manhattan island, there's no time to ponder the humanity of it all, because there's Ruskies to kill.
The first of two single-player levels that Infinity Ward has shown to date (along with Spec Ops Survival Mode, of which more later) was featured at Microsoft's E3 conference but deserves a recap.
You start off underwater, blowtorching through a metal grill in the gloom, listening to the sound of your rebreather and a few quiet instructions from your squad leader as the crosshatching melts away. Kicking free the loosened mesh, you emerge into a large space packed with what look like trucks, cars, buses, and New York's iconic yellow cabs. You're in the flooded Brooklyn tunnel.
You can see why it's flooded up ahead - the reinforced concrete wall has been wrenched completely open, presumably by an explosion, exposing the occupants to millions of tons of Upper Bay. Outside it's murky but beautiful, the riverbed clogged with a mixture of industrial drudgery, piping and broken military hardware. As you power your little one-man sub through the gloom and wait for motion on your sonar, you see a vast ship - you don't know whose - torpedoed and sinking into the depths ahead of you.
You swim under it and then more torpedoes glide overhead and your sonar starts to resonate, before the Russian submarine you've been sent to infiltrate fills your view. Your squad leader instructs you to hold position while it passes, which takes several long seconds - we're not used to stopping in Call of Duty - and then you advance and plant an explosive charge on its rudder. The force of the explosion cripples the sub and it has to surface, so you do likewise.
The water drains from your vision to reveal a pair of missiles smashing into a heavily battered Manhattan skyline, already dense with the competing pillars of dark black smoke sprouting from many similar gouges across the Financial District. Just then, a large wave rolls across your view and reveals the sub. You ditch your gear and climb onto its side, bringing up COD's iconic iron sights to quickly dispatch the Russian sailors who emerge to greet you.
Inside it's chaos, water flooding the corridors from unseen hull breaches, but the Russians continue to fight back, only to be turned aside by a mixture of your bullets and neat little set-piece takedowns executed by your squad mates (conveniently just within your line of sight).
Whatever the upheaval of last year's mutinous studio heads really did to the people making this game, all this is as slick and polished as ever, if not more so. If there's something your character can grab hold of in Modern Warfare 3, like a missile key or a porthole hatch, he's going to grab it and he'll look damn well-animated while he's doing it. If not, someone else will. There's so much texture to the world that you quickly forget the illusion into which you're being invited to buy and your limited role in perpetuating it.
Outside the sub, meanwhile, it's pandemonium, as you leap onto a motor dingy and make a run for it past the Russian ships into which the missiles you just launched are slamming. At one point your progress is threatened by a Russian patrol boat, which forces you to detour up onto the half-submerged deck of a stricken aircraft carrier, and the game slips back into slow motion so you can take out the Russian boat crew and blow the back half of it to smithereens by targeting the fuel lines.
With a characteristic jump off a makeshift ramp right at the last, the level ends as you board an amphibious Chinook and lift off. "All eagles accounted for," someone boats into headset as jets buzz past and over the evolving ruin of the Big Apple.
Before we have time to think about what we've just seen, however, an unseen Activision rep switches the TV input to another console and the next level, "Mind the Gap", which is set in London. The US may be on fire in the world of Modern Warfare, but things are still getting warmed up over on the other side of the Atlantic, where Infinity Ward says major cities are still heavily populated and many actions remain covert.
You join one such SAS sortie in the boots of Sgt Burns in Canary Wharf. The level starts off looking down from a chopper in night vision watching men load trucks. It's those pesky Russians again! Your CO orders you to hunt the trucks down and neutralise hostiles. The camera then picks up four guys approaching the east end of a warehouse and zooms down to join them - and you as one of them.
We've seen some of this before, fighting through the warehouse silently dispatching enemies, pausing to watch as snipers and other supporting units around us drop their tangos. Outside on the building site things get more heated as RPGs rain down and your adversaries suffer various industrial accidents, like a massive section of unplanted pipe stampeding into a group of soldiers while you calmly sit and reload behind cover of cinder blocks.
Soon though you reach the Russian trucks and new ground, racing down an embankment and into an exposed London Underground tunnel just as a Tube train gets moving. With no time to lose (when is there ever?), you and your squaddies mount a pair of nearby pickup trucks and give chase into the tunnels. You dodge oncoming trains and fire at soldiers leaning out of the Tube carriages, and at one point you race through a station past hordes of screaming commuters.
The radio chatter becomes urgent now and your squad mates in the other pickup reach the front of the train. They target the driver, but in the confusion something happens and they swerve into the leading carriage and explode, derailing the train, which flips onto its side and continues inexorably onwards, snapping tunnel supports like matchsticks as it gradually decelerates. The rest of the carriages twist and tumble in its wake as you fight to get clear, and then we fade to black.
With just a few more seconds to compose ourselves, we're ushered into a room next door where we're invited to go hands-on with Spec Ops Survival Mode. Presented in addition to the co-operative story missions (the likes of which made up Spec Ops in MW2) and of course competitive multiplayer, which we're not seeing at all just yet, Survival is a wave-based arena mode where you and a friend fend off waves of soldiers, dogs, choppers and whatever else the game can muster.
Beginning with a pistol, you mow down each wave and accumulate currency for kills, which can be invested in weapons, tools like sentry guns and outside support like riot-shield toting NPC team-mates and predator missile strikes, all of which can be upgraded with additional funds. The level we sample is a rundown military base with a warehouse, bunker, radio dome and the obligatory shipping containers, organised into several discrete combat areas linked by handy choke points.
It looks like wave design follows set patterns, but it keeps you on your toes nonetheless, with your adversaries not averse to strapping explosive charges to their dogs or throwing in a juggernaut - a heavily armoured brute with significant firepower to complement the efforts of the lower ranks.
Like Modern Warfare 2 and Black Ops before it, then, Modern Warfare 3 proposes not just to keep you busy with depth but also breadth - and we haven't yet heard properly about competitive multiplayer either. Treyarch's Black Ops introduced Wager Matches and other minor innovations, and while Infinity Ward and its new buddies at Sledgehammer undoubtedly could just reheat MW2 for online play, they are likely to want to recapture our imaginations by getting one over their Activision stable-mates where they can.
We still wouldn't expect dramatic overhauls, but then that's not Infinity Ward's style. Call of Duty didn't start with a nuke - it's always been about measured escalation. Measured to surprise, measured to provoke and measured to make you the centre of all that glorious attention to detail. Modern Warfare 3 should be no exception, for better or worse.