The sound team goes to great lengths to achieve this, and works closely with the Swedish army when they're out on manoeuvres. "On a joint venture with the Medal of Honor team to record weapon sounds, we had 84 microphones set up at different points. We had people five kilometres away up in the mountains, we had a rig down by the weapons... all these were synchronised".
The net result is that sound changes according to your relative position from the weapon, and the materials that constitute the environment around you. Strandberg then ably demonstrates this by fixing the in-engine camera to one spot in a woodland landscape, holding the fire button down and walking the onscreen soldier into the far distance. The rifle reports altered enormously as the distance grew, losing their sense of immediacy and bass-notes, and gaining that flat, echoey clack peculiar to gunfire in woodlands.
Back to the demo. When the courtyard firefight is dealt with, the squad moves on, and in short order our man is ordered down into a network of tunnels beneath a building to defuse a bomb that intelligence has been tipped off about.
Somewhere along the line, an earth tremor is felt, and commented on over the radio: like a hint of things to come. Bach drops into a maintenance room, finds the device and begins to defuse it, when an Iraqi guard walks in on him. What follows is a hand-to-hand brawl which borders on brutal. It can't hide its QTE ways, but it's an effective shock tactic dropped into a moment of tension.
When this is done, the team takes to the rooftops, and there's a honeyed quality to the early evening sun as it plays off the sandy stonework; it implies a vivid sense of time and location. Almost immediately, they come under high-calibre sniper fire, and hit the dirt. The squad does a belly-crawl across the rooftop, while chunks of concrete are literally punched out of the low walls around the roof.
DICE is keen to impress the fact that Frostbite 2 handles destructibility on a grand scale, and Bach soon proves the point. Switching from rifle to a one-shot anti-tank missile, he pops his head over the balcony and fires at the sniper's hiding spot in an adjacent tenement block. Windows explode outwards, showering thousands of glass shards and the building crumbles before us convincingly. Somewhere out there, Roland Emmerich dreams on approvingly.
The money shot of the demo is the final sequence. It's a running gun battle down a main city highway, while the squad receives close air support from a chopper. Just as Bach clambers into an abandoned technical to mount the machine gun, the threatened earthquake hits in earnest.
A massive shockwave ripples the pavement slabs, and a tower block shivers like a dinosaur and begins, oh so slowly, to fall towards the camera. The chopper is right in its path and I feel a tremendous urge to shout, "Look out behind you!" Just as the pilot realises, it's swatted out of the sky as the building tumbles towards the player.
Fade to black. For now, it's a wrap. And I'm puzzled. Battlefield 3 is visually startling, and a technical marvel, but I still don't know what it's really about. Later, I ask Bach what the hook of the game is. What will make people want to play it?
He simply says, "We're making the best modern-era shooter ever made." Given recent form and the strong technological base they're working from, not to mention my personal fatigue with the latest crop of military-FPS blockbusters, I'm inclined to believe him. I certainly want to, at any rate.