What is it, exactly, that makes Far Cry 2's multiplayer mode so much fun? Is it the class system, a carefully designed structure that encourages you to develop your skills along set styles of play? Is it the injury mechanics, the lack of easy healing that makes combat a brutally swift affair? Is it simply the engaging African setting - or perhaps the little details, like the deliciously wet 'thwack!' that accompanies someone getting shot? Perhaps it's all these things. In any case, we have no qualms about saying that Ubisoft Montreal has totally delivered the goods.

If you're one of the many people waiting for Far Cry 2, you'll probably be fairly clued up about the game's little spins and quirks on the standard FPS format. The first thing you should note now is that many of these tricks are also present in multiplayer, albeit in a slightly reworked style. Weapons still degrade over time, but they do so at a much reduced rate; Ubisoft told us that early deathmatch builds featured the same degree of jamming as the single-player game, and that this resulted in matches full of pissed-off mercenaries toting guns that didn't work. Now malfunctions are only likely if you've been alive for quite some time, so dodgy hardware will only be a major consideration for the best players.

Indeed, you'll soon discover that death is easy to find in a Far Cry 2 deathmatch. Two or three rounds will be enough to put you on the ground - combat is certainly closer to the deadly firefights of COD4 or Counterstrike than it is to the Halo series, where a brief retreat will give you enough time to recharge your shield. There are no magical health packs here: if you get shot up but don't die, you'll have to find some cover and use LB/L1 to dig the bullets out of your flesh using a penknife. This is a pretty grisly process to watch, and it takes time too - leaving the enemy plenty of time to close in on your spot. The upshot of all this is that battles feel messy and very dangerous - even when you've honed your skills, you'll never feel completely safe.

Of course, when you're roaming the streets of an African shanty town, it pays to have a friend by your side. In Far Cry 2's main campaign you have access to buddies who will risk their lives to rescue you in combat, and in multiplayer you'll be able to perform the same service for your team mates. Assuming the opposition doesn't completely destroy you (with a rocket, for example), there will be a brief window of opportunity after an attack knocks you out of the fight. If a friend can get to you before you bleed to death, they'll help you back up to your feet and you can carry on fighting. However, there's a catch here: your attacker might still be in the vicinity - and if they've not finished you off, there's probably a reason for that. Remember the sniper scene from the end of Full Metal Jacket? In this game, rescuing a fallen comrade is extremely risky. All the same, you'll want to give it a go because a) you'll feel like a champion if you pull it off and b) saving a friend means their kill isn't counted on the other side's score. In a close team deathmatch, this could be the deciding factor that brings you victory.

There's more of an emphasis on team work than in other multiplayer FPS games

Hopefully you're beginning to get a sense of Far Cry 2's emphasis on team work. Sure, there's a free-for-all mode, but it's under the more complicated setups that the game really comes into its own. Aside from standard and group-based deathmatch, there's Capture the Diamond (a bling-based Capture the Flag) and a slightly more innovative mode labelled Uprising. Here each team is randomly assigned a leader, who must then occupy and take over three control points on the map. Once this is done, the opposing leader must be assassinated in order to claim the win.

It's essentially a cocktail of two inherently familiar multiplayer modes - VIP and Assault - but for some reason it works really well. The first half of any Uprising match is a bitterly-fought affair, as both teams attempt to help their captain push forward. As soon as one side takes the upper hand and claims their third checkpoint, there's a sudden rush of activity as everyone rushes to get at the compromised leader - and yet it's all too easy for the attackers to overstretch themselves. If the defenders can take out the opposition, they'll have a chance to reclaim some ground and get back into the match.

One thing we've not even touched on yet is Far Cry 2's strict class system, and the resulting restrictions on your arsenal. In what may initially seem like a backward step, players are unable to pick up weapons from the bodies of other mercenaries. Instead you are forced to stick with the arsenal allocated to your chosen class. There are six categories to choose from: the Commando is an all-rounder with a machine gun and molotov cocktails; the Guerrilla gets a shotgun and focuses on getting up close and personal; the Sharpshooter is the mandatory sniper class; the stealthy Saboteur gets silenced weapons; the Rebel wields a flamethrower; and the Gunner gets access to all the heavy artillery.

None of these classes sound particularly original, but that's not the point. Between deaths you're allowed to switch about as you please, but once you've notched up a bit of experience you'll be given a diamond which can then be spent on upgrading a class of your choice, granting access to better weapons. In casual games these gems will be dispensed fairly freely, but in ranked matches you'll have to put in some serious graft before you're rewarded. As a result, you're forced to really think about which play-style suits you best. You'll be able to reset your diamond allocation at any given time, but doing so will deduct one glittering stone from your total - so you better consider this option carefully. While we imagine that there will be some gamers who won't like the class system, the truth is that it forces you to think about tactics. You can't handle everything yourself; you have to pick a role that will support your team, and do it as best you can. We like this.

We expect Far Cry 2's multiplayer to keep us occupied for months on end

A total of 14 maps will be included with the initial game, but if the map-making community takes the much-touted editing tools to heart, the hope is that there will be hundreds of stages available within a relatively short space of time. Ubisoft predicts that this will reduce the importance of knowing a map inside-out, since there will be simply too many to learn. The pre-designed levels we sampled offered a good range of built-up urban areas and wide open spaces, so there was plenty of opportunities for all weapon types. Having said that, we did notice that heavy explosives seemed to rule the roost - one of our fellow journalists upgraded to a scoped grenade launcher that thoroughly toasted all comers. The developers were still balancing this area when we last spoke to them, so hopefully the final build won't favour any weapon excessively.

The usual format of a morning press event is that when everyone breaks for lunch, the consoles are abandoned for a while. During last week's Far Cry 2 promo, a large swathe of hacks remained glued to their controllers while the nearby buffet went cold - surely yet another sign that Ubisoft Montreal is on to a winner. We're sure that it's the single-player game that most gamers are waiting for, but it's still good to know that there's a hefty set of deathmatch options to back it up. On the basis of what we've played, we reckon this could garner quite a sizeable online following - a following that will certainly include us.

Far Cry 2 is due out for PC, PS3 and Xbox 360 on October 24.