Astonishingly violent, conservatively assembled. That was how Tom described his first impressions of Killzone 2's single-player campaign way back in July 2007, and it provides a rather convenient bridge into the multiplayer side of things, as revealed in the current invite-only beta.

While other first person shooters have been busy tweaking and remixing their multiplayer components, Killzone 2 seems to be taking it back to the old school with a deliberate focus on tense, brutal action with the minimum of distracting frills. In fact, for all the talk of Halo 3, Resistance 2 and Call of Duty, the game it bears most resemblance to is the original PC version of Rainbow Six, the gritted-teeth centrepiece of so many LAN parties ten years ago.

Killzone 2's biggest innovation comes in its class system, where you can combine elements of two different disciplines to create a hybrid class that best suits your preferred style of play. Even so, the classes on offer will be instantly familiar to anyone who has spent time on the Battlefield or Team Fortress series. Scouts are the default snipers, armed with a cloaking device and the ability to spot and mark enemy units for their teammates. Tacticians can deploy spawn points and call in air support, making them useful infiltrators. Saboteurs can disguise themselves and plant bombs, while Engineers erect automated defence turrets and can repair damage. The Medic and Assault classes are much as you'd expect, offering the obvious combat and healing options.

You won't get to try any of these features though, at least not to begin with. Each class must be unlocked by levelling up through the game's military ranks, along with the ability to create clans and the expected additional weaponry rewards. It's a curious decision and one that seems at odds with the game's natural audience. "This system allows for a very natural learning curve throughout because the player is introduced more slowly to every feature, one by one," claimed Eric Boltjes, from developer Guerilla, while showing off the multiplayer modes to Kristan this August.

It's hard to imagine who will need such a gentle introduction to such a tried-and-trusted class system, however. It only takes a few minutes play to realise that Killzone 2 is as hardcore as shooters get, and it's unlikely that hardened FPS veterans will benefit from having to grind their way through the ranks in order to access all the toys they've come to expect.

This means that every player starts the game as a classless grunt, with no auxiliary abilities and a choice of just two rifles and two pistols. These weapons are thankfully extremely effective (perhaps too effective - but we'll get to that later) and you can also boost your chances by joining a four-man squad. Since the game supports up to 32 players, this means that each side can have four organised squads at work rather than sixteen loose cannons. Apart the clear tactical advantage of this division of labour, the biggest benefit of squad play is that you can respawn alongside the squad leader, rather than back at the base, as well as use a private chat channel to coordinate your movements with your comrades.

In terms of gameplay on offer, the beta offers all the proposed game modes and three of the game's maps on which to try them. Body Count is your basic Team Deathmatch mode, but there doesn't seem to be a traditional "every man for himself" Deathmatch option. Search and Retrieve is your Capture the Flag variation, while Search and Destroy takes much the same form but swaps retrieval for planting bombs. Assassination is perhaps the most interesting mode, randomly selecting a player as the target and tasking their team with protecting them while the opposing side does their best to kill them to bits within a strict time limit.

All of these modes can be mixed up in Warzone mode, which allows the host to serve up a conveyor belt of challenges all on the same map without having to dip in and out of the lobby between game types. While not particularly innovative, it's still a thoughtful addition and one that keeps the gameplay moving and reasonably varied without spoiling the flow.

And what of the maps? They're good. Great even. With the game modes directing everyone to attack or defend the same objectives, the maps are freed from the typical artificial arena designs that funnel you into the same choke-points over and over. The larger maps strike a solid balance between open ground, claustrophobic interiors and elevated positions which means there's always a multitude of ways to approach any given situation - a facet of the game that is greatly enhanced by shrewd squad play. Radec Academy is the smallest, and most traditional, of the trio. Featuring two buildings divided by an open plaza, with an underground tunnel and opposing spawn points on each side, this is the map that really throws the players at each other most frequently and is best suited to Body Count mode.

Salamun Market and Blood Gracht are much larger, offering sprawling streets and winding alleyways, with plenty of interiors for ducking out of danger or sneaking past enemy forces. The visuals fall into the current trend for bleak browns and greys, but there are enough incidental details to make it a successful aesthetic decision rather than just a lazy one. Climb up to the higher levels and the wind howls and whips around you, sending banners and cloth fluttering angrily. Scenery objects are affected by physics, but this isn't Half-Life 2 and the game wisely doesn't waste time or processing power on letting you hoof empty boxes and cans around the place. The frame rate seems solid and while the occasional laggy player can be seen popping around the map like the witch from Chorlton and the Wheelies , that's clearly a result of their troubled connection rather than any flaw in the game code.

Gameplay is fast and vicious, then, with precious little time between the first bullet hit and your writhing body (which can be revived within ten seconds by a medic) hitting the ground. It's another area where the Rainbow Six comparison feels most comfortable - if you stray into somebody's sights, chances are you're going down. Equally, get someone in your sights, even from a distance, and chances are you'll be able to take them down with little more than a quick volley of shots. There is a recharging health system, but it rarely gets the chance to do its thing because the default weapons are so brutally accurate and devastatingly effective. Ammo and replacement weapons, however, are virtually non-existent. If you prefer the sort of shooter where you can stand in the open and soak up damage, while rifles and rocket launchers are scattered about the place like used bus tickets, then Killzone 2 won't be for you.

This ruthless edge certainly lends itself to the sort of taut and unforgiving gameplay that hardened FPS addicts will favour, but it can also lead to awkward balancing problems since it automatically favours those playing defence. A squad of soldiers behind cover can be all but invincible, at least within the time limits offered for the various game-types and with the default weaponry. Your tactical options drastically improve with more classes to choose from, but there's a tough attack-die-respawn-attack cycle waiting for most new players as they battle their way to a decent rank.

Killzone 2's multiplayer certainly impresses with its technical stability and stark, oppressive atmosphere. Where it perhaps struggles a tad is in its adherence to a savage style of play that has come to seem old fashioned in recent years. This is an online game that demands much from the player, but seemingly will only offer its rewards grudgingly and in small increments. However, there are many who will relish this back-to-basics approach, and for those dedicated players the lack of surprising new twists on the deathmatch formula won't matter one little bit.

Killzone 2 is due out exclusively for PS3 in February 2009.