When in Rome: knife everyone, it seems. The original Assassin's Creed laid the groundwork for the series' story-based campaigns, plots which served to develop its Dan Brown-style lore of Templars alongside a subplot featuring that bird from Veronica Mars. The concern that multiplayer would conflict with the series' strong narrative focus provoked enough fans and forumites to get a bit on edge over the idea of letting players run riot in Renaissance Italy.
Brotherhood's multiplayer is only loosely fitted around the narrative of the series - the conceit being that you're playing a modern-day Templar-in-training who, along with seven colleagues, is hooked up to the Animus to take on the identity of an assassin. But ignore the absentee Desmond and Ezio for a minute, because the greatest gift AC multiplayer can give you is the fact that the living, breathing city remains completely intact. The world of Assassin's Creed is as fully realised as it has been in any single-player instalment, pop-full of heaving masses of citizens; citizens in mid-conversation with one another, citizens who will wobble about when you dash through them. What could have been designed as a simple set, a poor man's imitation of AC's city-du-jour, is a writhing, fully fleshed out metropolis. Both multiplayer modes are playable on two maps, Rome and Castle Gandolfo, and a third, Siena, to be unlocked by the community in Beta. There's still real humanity in the cities, and a real sense of impending danger.
Where single-player could often devolve from a matter of stealth into a basic chase routine, there's a methodology to multiplayer that forces you to be aware of - and I mean this quite literally - every step you take.
For one, the game discourages you from running amok. Multiplayer puts you in the shoes of both an assassin and the target of an assassin, meaning you are encouraged to fit in seamlessly with the crowd of NPCs as you make your way toward your victim. Your aim is to go unnoticed, to confuse your own hunter so that they mistake you for a random, AI-controlled citizen. It's a continuing game of cat and mouse: blend just enough to remain unnoticed, but retain enough of your typical gamer tendencies to keep an eye out for someone acting out-of-place.
If you reckon someone is on your tail then you can call upon one of your character abilities and perks. Knives slow your target down, while Smoke releases a smoke bomb that will immobilise them entirely. Other abilities effect the NPCs around you: Blender transforms the surrounding crowd into clones of your character, while Auto-Bash increases the number of NPCs you can run into without becoming unbalanced. None of these are particularly necessary to gameplay but they lend a degree of complexity to what could become a simple game of stealth-tag. Smoke, for instance, will wall off an enemy behind a cloud, giving you a moment to double back and stun or kill him.
Even the map is designed to complicate the chase. Chase Breakers are built-in interactive elements designed to help you escape if and when you're being pursued. They are doorways that will sparkle to let you know they'll slam shut the minute you enter them, forcing anyone behind you to find another route around. There are lifts that will take you to a rooftop, or falling platforms that will cut the chase short. Then you have the AC classics: hay stacks to dive in, walls to climb. In fact, climbing mechanics have been re-designed specifically for the speed of multiplayer. Where single-player will introduce you to walls that can be scaled at different speeds, multiplayer allows you to climb incredibly easily, and it's a hell of a lifesaver.
In the first of the two modes, Wanted, you're set up with seven others and given one player to assassinate. Someone else is also assigned to hunt you, and depending on how well you perform you can become the target of multiple players at once. To the top left of the HUD are red icons that represent how many people are searching for you at that point in the match. The game is continuously attempting to level the playing field. Lower ranking players will be given an easier time, faced only with one pursuer until they work their way up and start raking in points, while higher ranking players will find themselves followed by handfuls of assassins at once.