As I approach the top of a frozen ridge I pause for a moment, staring down into the grey sea below. The icey waves chop and foam, and above them flecks of snow are borne aloft on coastal winds. The landscape is cruel and yet almost unbearably pretty, and if I had time I could sit here for ages. Unfortunately I can't do that right now; I'm in one of Sony's private E3 rooms, and three impatient Dutchmen are breathing down my neck. Everyone wants their turn, it would seem - and under the circumstances, that's hardly surprising. As things currently stand, Killzone 3 may well be the best-looking game in existence. (It's hard to be definitive about these things, but it's certainly a distinct possibility.)

Three separate chunks of Killzone 3 are up for grabs in today's code. The first kicks off with Sev and Rico - the Special Forces frontmen of the past two games - leading an airborne attack on the alien Helghast, using some kind of jet-powered craft to soar through the hostile skies of an Arctic landscape. After several swooping raids on Helghast-controlled oil rigs, the ships are blown out of the air by a powerful counter-attack; from here the mission continues on foot, with running gun-battles leading to the wreck of a crashed cargo ship. The second section picks up shortly after this point, with Sev (and therefore the player) assuming control of a prototype enemy jetpack - one of Killzone 3's most eagerly-awaited features - and then using it to sabotage an anti-air cannon on one of the rig-bases. Finally, the third and briefest taster finds Sev and his buddies going up against a staunchly-defended Helghast stronghold, using a powerful new rocket launcher to level the playing field - both literally and figuratively.

In the case of the first section, the blockbuster action stakes are further enhanced by the fact that I'm playing in 3D. I'm not sure whether it's the game or just the need for some kind of mental adjustment, but initially I find the whole stereoscopic effect to be a bit disorientating. The opening moments are a rollercoaster of swooping jet-craft, roaring minigun fire, and a desperate scramble to locate and neutralise RPG-packing Helghast defending their rig. There's no control over the camera, what with this being an on-rails set piece, and with the added 3D perspective it's all a bit much to take in. It's looks spectacular though, particularly when a heavy blast sends steel pipes crashing down onto a section of the rig's walkway: the floor gives way with a metallic clatter, sending Helghast troops tumbling into the freezing depths below. There's barely time to enjoy the moment, as Sev's ride is already circling around for another attack.

A while later, once the action has returned to the ground and I've regained control of my own two feet, my brain settles into the 3D effects. It's still a bit odd, but there's a certain intensity that stems from being able to see the depth of the game world. We're not fighting across a flat plain, here: the snow-covered terrain is all slopes and mounds and half-buried obstacles - the latter proving invaluable cover from the Helghast threat. The gunplay itself is immediately satisfying and surprisingly pace-y to boot. I nip from cover to cover, zooming in on yellow-eyed faces and letting rip with my beefy assault rifle. I begin to forget about the novelty of 3D and concentrate on the battle at hand; in retrospect, this can only be a good sign.

It's only when I reach the wrecked cargo boat that I begin to take notice of the effect once again. Like its predecessor, Killzone 3 gives the player a narrower field of view than the average first person shooter. It's particularly noticeable when you're fighting indoors, and here the 3D helps to amplify the claustrophobic feeling of the ship's rusty bulkheads and clanking metal floors. As I nervously round a corner a Helghast soldier catches me by surprise, and suddenly I'm watching one of the game's new melee kills - Sev violently forcing his knife into his rival's eye socket. Apparently these close-up executions will make use of nearby scenery. If you perform one while near the edge of a railing, for example, you'll hurl your foe headfirst to their death.

As I clamber down into the open-air body of the cargo ship, I first encounter the new jetpack troops. There's a strange spider-like quality to these guys, perhaps due to the long steel arms that extend forward over each of their shoulders. Aside from their added mobility, they don't seem too difficult to despatch; then again, perhaps they're just easy pickings here because this is (presumably) their first appearance in the game. At any rate, they certainly look amazing when slain: one stumbles over and explodes into a rich orange fireball, while his mate attempts to fly off and instead smashes into a nearby wall, Star Wars slapstick fashion.

Naturally the real fun starts in the second demo, when I get to try out one of these packs for myself. As it turns out the Helghan jetpacks don't really allow for complete, infinite flight; instead they offer a sort of extended, rocket-fuelled leap. Holding L2 launches you skyward with a fierce tearing noise, then you can hit X to get short boost forward. At this point you better have some kind of perch under your feet, because the pack won't work again till it's had a moment to cool off (again accompanied by a very more-ish sound effect). It's quite tricky to use this system at first, and my first two attempts result in comic suicide as Sev runs out of juice and drops like a stone into the sea. Before long, however, I find myself leaping about with aplomb, though there's still something quite funny about the clumsiness of my leaps. There's a bit of skill required for the smart use of the pack, but this makes it all the more rewarding when you finally get the hang of the mechanics.

The centrepiece of the second demo is a return to one of the rigs we saw earlier, on an impromptu mission to blow up a large gun emplacement. The first part of this task involves a bit of exploration (and in my case, a few stupid deaths) as Sev flits about the metal legs and underside of the rig. As soon as I reach the main deck, however, all hell breaks loose, with dozens of angry Helghast appearing to defend the base. You can't use the cover system while wearing the jetpack, so the only option is to use grenades, to keep moving, and to lay down massive swathes of fire with the in-built machine guns. The open design of the rig grants plenty of scope for hopping about between levels, and ultimately I'm left feeling like a termite with a Rambo fixation.

Moments later, I'm planting a demolition charge underneath the AA gun. As in Killzone 2, the arming system requires you to twist the controller about - a needless touch, perhaps, but one that's still rather fun. The emplacement goes boom, and shortly after the jetpack demo draws to a close. I'm slightly disappointed to say goodbye to my new toy, but at least the next section offers the opportunity to blow lots of stuff up.

The final interlude is really just here to showcase the WASP - a new rocket launcher that launches projectiles in clumps of three. You're not limited to firing three at a time, of course: if you spam the trigger you'll spew out a rain of explosive death, with slender white missiles leaving a wispy trail in their wake. In truth, this final slice of gameplay seems a bit straightforward compared to everything that's come before, since the WASP completely decimates everything the Helghast can throw the player's way. Sev can only carry 30 rockets at a time, but that's more than enough to wipe out legions of troops and even a couple of tanks - especially since there's a handy little ammo stash to use every 15 feet or so. Still, this third demo does a grand job on one front: it demonstrates Guerrilla's revised approach to destructible terrain. In short, there's a lot more of it: blast away at a stone column and cracks will form across its surface. Blast again, and hefty chunks of concrete will slip out and fall to the ground. It looks great; if you tend to get excited over this kind of detail, this game will send blood rushing to the places Teacher told you not to touch.

So yes indeed, Killzone 3 looks awfully pretty - and the E3 code isn't even at the beta stage yet. The early signs are that the whole 3D aspect will work rather well, but I'm still not convinced that they'll be worth buying a new TV for. On the other hand, I have little doubt that Killzone 3 could help to sell a shedload of new PS3s, because as far as console exclusives go, this will probably be the hottest girl in the club. More importantly, the game's action is already seriously tasty, offering some of the best thrills of anything I played at this year's E3. February 2011 can't come soon enough.

Killzone 3 will be released in February 2011, exclusively on the PS3.