By Golly, it's loud. Treyarch boss Mark Lamia has just wrapped up his presentation for Call of Duty: Black Ops, and I think my skull has been shattered by a giga-decibel sonic boom. Seriously, I keep rubbing my ear to see if I'm leaking any of that straw-coloured liquid that comes out when you fracture your bonce. About five minutes ago, when that helicopter swept in to take down that Vietnamese tower block, one of my eyes ruptured a bit.

Naturally, when we're actually playing the game for ourselves - in November of this year, if all goes to plan - we'll be able to turn the volume down. But maybe we shouldn't: after all, CoD has always worked best with all the dials cranked up to full, when the bullets are flying and half the world appears to be blowing up right in front of you. This is a franchise that's always delivered a special brand of it's-all-gone-to-Hell chaos, and Black Ops is already looking to be just as apocalyptic as its predecessors. The story follows a group of as-yet unrevealed military experts as they take part in secret, off-the-record military operations around the world; the exact time frame is yet to be revealed, but we know that the game will cover the 1960s and beyond - a span that allows Treyarch to delve into a whole range of tumultuous historical conflicts.

I know a lot of people found Modern Warfare 2 to be a bit one-note in its dedication to big bangs, and it's certainly fair to say that there weren't too many quiet moments after "Cliffhanger" - that sneaky mission in the snow. You might feel that you're not yet ready for another helping of military bedlam, but I can tell you right now that I was extremely impressed with the two levels that Treyarch showed off this week. The studio has a lot to compete with - particularly the success of MW2, and the public relations shitstorm that followed - but Lamia maintains that the team has simply been concentrating on making the best game possible. And on first impressions at least, the fruit of their efforts is looking pretty damn exciting.

The demo kicks off in a slightly unexpected fashion, on the sun-drenched deck of an aircraft carrier. The player character pulls down the visor on their flying helmet, heavy breathing echoing in our ears, and we follow our co-pilot over to a SR 71 Blackbird - a rather evil-looking high altitude reconnaissance plane. We climb the ladder up into the front seat, the cockpit closes in, and a wave of pre-flight radio chatter washes over us. And then we're off, roaring down the runway at unstoppable speed. Suddenly a prompt appears on screen, telling us to pull back on the left stick. Are we to assume complete control of the craft?

No, it would appear not - but what happens next is arguably even cooler. Following a quick fade-to-white transition, we find ourselves cruising high in the Earth's atmosphere. Our view dips towards a screen mounted in the Blackbird's HUD; there's a bit of fiddling with the switches and dials that flank the screen, and then we find ourselves looking at an overhead view of a Russian mountain range. We're told to scan the area until we find our squad, their heat signatures making them stand out brightly against the scenery. We've seen this kind of thing before with the AC-130 sections in the Modern Warfares, but today we won't be bombarding the enemy with shells: this is a secret black op, after all, and subtlety is the name of the game; the Blackbird is here to provide information about the movement of nearby hostiles. There's an enemy convoy heading towards our boys' position, and we're instructed to direct them to cover. We do so, using what appears to be a simplified RTS-style command system. The player guides the squad towards some kind of building (it's kind of hard to tell on the monitor), then they head North away from the road.

At this point, we transition again into the viewpoint of one of the squad members. The action kicks off with the player hiding in a snow-covered ditch, as a large group of Soviet soldiers stalk by. Once the enemies pass, we crawl out of our hiding spot. Here, finally, is the classic Call of Duty perspective. We make our way down the side of the mountain, pausing occasionally to take out Russian guards in hushed, co-ordinated attacks. Our weapon for the first half of the mission is a scoped crossbow, our vision taking on a fish-eye distortion every time we take aim on the back of an enemy head.

There's a certainly an air of familiarity here, in the tense atmosphere punctuated by bursts of violent action, but the scenery is indisputably top notch. The mountain landscape stretches before us as we move downhill, thick gusts of snow sweeping across our vision, and eventually we reach the top of a substation - a concrete bunker built into the side of a steep drop. It's time for another change-up: the squad strap themselves to the balcony at the top of the descent then climb out over the ledge. We rappel down the side of the chasm, using the left and right triggers to control our descent; as we reach the bottom we reach a glass window. As we swing towards the portal the player spiderwebs the glass with a burst from his silenced assault rifle. The window smashes as we crash through into the room, and the surprised Russian occupants are obliterated via slo-mo massacre.

The substation itself is actually just the first port of call on the assignment, with the overall target being a large radar relay further down the mountain. I don't want to dwell too heavily on the rest of this level as Treyarch also showed off a whole other mission that I've yet to cover, but the short summary is that from here on, the job gets a lot louder. It'll apparently be possible to play through the entire stage in stealthy fashion, but as we approached the main base the demo player decided to take a more dramatic approach: he switched back to the crossbow, and then targeted a large fuel tanker with what appeared to be an explosive bolt. Are we getting multiple ammo types for all our weapons? It's not yet clear, but in this instance the shot certainly had a major impact, whipping the dastardly Ruskies up into a furious, bullet happy response.

The remainder of the Russian mission played out at breakneck pace: a dash through the facility, blowing away soldiers at close range with a SPAS-12 shotgun, until the player found and sabotaged the main power source for the dish. The pace of combat in the last section was typically fraught CoD stuff, with enemies pouring in from all over the place and the odd bout of stabbing when someone got too close. Just for added kicks, the mission ended with a mad dash to escape a colossal avalanche that came crashing down on the base. Again, the visuals here were extremely impressive, with huge freezing clouds swirling all around as the player made a desperate sprint for safety. And what with this being a Call of Duty game, safety meant jumping off the edge of a cliff, ice crystals forming at the edge of the screen as the player plummeted into the white void.

While the snow-bound Russian level took a while before it finally worked up to the standard CoD madness, the second level seemed inherently insane from the off. Here the gist seems to be that the player and his pals are tasked with retrieving some important files from a CIA office. This wouldn't be a big deal under normal circumstances, but unfortunately the building in question is in the city of Hue, and one of the bloodiest battles in the Vietnam War is currently underway.

It's madness right from the start: we begin by trying to rappel down to the ground from a helicopter, but the chopper in question gets hit by a rocket and goes spiralling out of control. There's a nausea-inducing moment as the player whirls through the air on the end of a rope, before finally managing to swing through the window of a nearby building. This show-boating intro leads to a series of fierce gun battles through the interiors of several ruined buildings. There's an atmosphere that echoes the later parts of MW2's campaign, when it actually felt like you were fighting through the end of the world: everything is trashed, smashed or on fire. Vietnamese propaganda spews from some unseen tannoy, and when we catch a glimpse of the sky outside it is streaked with oily smoke, lit up with tracer fire. Helicopters are patrolling the airways, and they're not just there for atmospheric purposes either: at one point an entire room's worth of foes is utterly decimated by a sort of chopper drive-by.

Again, the action as a whole feels very typically Call of Duty, but the execution is pretty much flawless. It's a dark level, both visually and tonally, and everywhere you look the world appears to be in ruins: snapped cables, crumbled chunks of wall and the exposed innards of mortally-wounded buildings. There are some particularly nice particle effects on display too, and given the fact that the fighting is almost constant, with something blowing up or collapsing every ten seconds, you'll see a lot of them. But perhaps the most pleasing aspect of all is the fact that it feels like a warzone. A dirty tank rolls around a corner, and as you walk alongside you notice someone has daubed graffiti on the side. An innocent civilian dashes out of a room with a dazed expression, his palm extended in supplication. War is hell, and Black Ops knows it.

So, business as usual then? Perhaps. Even among the more hardcore fans, there's often a sense that Treyarch is viewed as simply the "other" Call of Duty developer, but this time around there's a sense that the studio may try to steal the spotlight. With Infinity Ward half dead there's a real opening for Treyarch to step up, though it'll be a gargantuan achievement if Black Ops manages to equal the impact that Modern Warfare 2 had last November. For the time being, there's plenty to be positive about. The game already has that lush, big-budget feel, and the action looks as wild and gritty as ever. There's a lot of potential in the setting, too: Treyarch hasn't revealed the full scope of the game yet, but it's strongly hinted that it'll stretch far beyond the 1968 setting of these demoed missions.

Alongside the single-player campaign there'll be a standalone co-op mode for up to four players online, and two players in local split-screen. It's safe to assume that the competitive multiplayer mode will be huge, and as for a repeat of World at War's Zombie mode... well, nothing's been confirmed or denied, but there's bound to be something; the developers would be fools to ignore public demand. Black Ops represents a big opportunity for Treyarch: the company knows it, and we know it too. And however you feel about the Call of Duty franchise, I suspect you want to see how this one will turn out.

Call of Duty: Black Ops will be released on PC, PS3, Xbox 360 and Wii on November 9.