Imitation is the sincerest form of flattery, as the old saying goes. What the old saying forgets to add is that the imitation is all the more effective - and a good deal less sincere - if your source material is largely forgotten. Gears of War may not have invented the concept of single-button cover systems (take a bow, kill.switch!), but since that was the game that made the mechanic so popular, no-one really cares about the one that did it first (get off the stage, kill.switch!).

In the case of Assassin's Creed Brotherhood's multiplayer, the overlooked source is The Ship - a Half Life 1 mod that eventually got its own commercial release, one that is now played by all of about four people. Unfortunately The Ship lacked sales, and as a result it largely went by unnoticed. This was something of a shame, as the core concept was excellent. Participants found themselves dumped on a commercial cruise liner, along with a large crowd of NPCs and human-controlled competitors. Each player was then given a target to hunt down and kill - an objective tempered by the knowledge that you yourself were the intended prize of another would-be assassin. Crucially, the AI characters were visually indistinguishable from their potentially human counterparts, leading to a stressful situation where everyone crawled around the map, pretending to be bots and fearfully peering over their paranoid shoulders.

The Ship is all but dead these days, but the game's spirit now has forebear of sorts. Barring a few changes, Brotherhood's multiplayer is a beefed-up descendant of the same old murder-em-up hijinx. A few things have been ditched, naturally. The Ship gave players a series of Sims-like needs that had to be catered for - notably a hungry belly and a leaky bladder - resulting in a near-constant requirement to stay on the move. The whole idea was to prevent camping and to keep the gaming ticking over at a nice pace, but since Brotherhood's matches are already fairly speedy, these redundant mechanics are nowhere to be found. Besides, it would probably ruin Ubisoft's carefully-crafted ambiance if you had to stop every two minutes to take a gushing piss all over Renaissance-era Rome.

Aside from the absence of potentially fatal toilet trips, Brotherhood's core multiplayer plays a lot like The Ship did back in the day. You creep about with one eye on your radar, desperately trying to find your target and hoping against hope that you won't get snuffed out by your unseen stalker. It's gripping stuff, and the whole experience draws heavily on the tense atmosphere that Ubisoft has perfected over the course of the franchise. Crowds have always featured heavily in the Creed series, but while we're used to playing the all-powerful predator lurking among the public, here you have to contend with the knowledge that there are up to seven other killers out there. Is that courtesan on the corner a rival player, waiting for their moment to strike, or is it simply another AI-controlled passer-by? Either way, you're going to find out soon enough.

There are several different character skins to choose, including nobles, doctors in beaked masks and podgy inventors wearing anachronistic John Lennon spectacles. Despite their different physical appearances (and a varying set of execution animations), each of these characters has exactly the same basic abilities. With hindsight, this is a smart design choice on Ubisoft's part; while the setup might seem to be crying out for some kind of class system, this would invariably have led to situation where one character was favoured over all others. As it is, there's no advantage to choosing any one skin - and so hopefully this should ensure a broad mix of avatars when the game finally launches.

While each of the character models has the same basic moves as their peers, each player also has to pick from one of several ability loadouts. There are two skills in each of these sets, ranging from hidden wrist-guns to temporary crowd-blending moves. At the moment, it's the defensive options that seem to hold the most value: if you're close enough to shoot someone, you're probably close enough to push your blade through one of their lungs - although it admittedly feels great to blast someone as they attempt to clamber up the side of a building. On the other hand, when your nemesis finally reveals themselves and is about to pull out all your important squidgy bits, it's a huge relief to have some way of setting up an escape. Botched assassination attempts result in brief, heart-pumping chase sequences where the victim-to-be must flee their rival; if they manage to evade their pursuer for long enough then the contract on their life will be cancelled. At this point the failed killer is given a new contract, and the game carries on as before.

Even outside of these chases, acrobatics and free-running play just as big a role as they have done in previous Creeds; the big difference now is that you have to be very careful about when and where you exercise your talents. Your personal radar only gives you a rough idea of where your target is and how far away they are, so it pays to get yourself into a spot where you can keep a close eye on your surroundings. If you climb up onto a roof then you'll have an excellent view of the map, but you'll also stand out like a sore thumb - in fact you may as well hold up a sign saying, "Kill me now!" There's a peculiar thrill when you spot a human-controlled character scrambling up a wall. Even when the player in question isn't your current target, there's something pleasing about suddenly spotting a "real" person emerging from the sea of anonymous drones. And of course, if the player in question is the object of your homicidal intentions, there's a clear dilemma: do you give chase subtly, on the ground, or do you climb up and go after them over the rooftops - exposing yourself to similar levels of risk?

It all adds up to a dynamic and rather refreshing alternative to the common or garden deathmatch. There's a pleasing emphasis on skill here: the game rewards careful assassins and punishes those who go on frantic, stab-happy rampages. At the moment, the only real problem I can foresee is that there may not be much scope for gameplay variations - and in the long-term, that's one of the key ingredients that keeps people coming back for more. Beyond that, there's a risk that the masses will ignore Brotherhood's multiplayer simply because it's different and not easily categorised. That would be a pity, because I've certainly really liked what I've played of it so far. Still, there'll be plenty of people picking up the game for the single-player campaign, and I'd imagine that most of them will be prepared to at least give it a try. It's bound to do better than The Ship, at any rate.

Assassin's Creed Brotherhood is due for release on Xbox 360, PS3 and PC on November 19.