The mode has been teased to be faster and more intense, while still offering Halo's trademark gameplay style.
Players can customise their own Spartan IV both in terms of looks and abilities, with the chance to customise play styles and build unique loadouts into matches.
Two maps have been revealed. Warhouse is a civilian manufacturing facility orbiting a gas giant, and is a spherical map with a focal point near a centralised mech platform.
Meanwhile, Wraparound features a Forerunner solar facility that generates artificial sunlight and energy for a shield world, and offers circular catwalks and corridors for multiple routes.
Halo 4's maps will be designed to tell more of a story, visiting locations beyond those explored in the campaign.
343 Industries will also offer a compelling backstory as to why the familiar red and blue Spartan teams will be fighting one another.
Maps are being designed specially for competitive play, and won't be repurposed from campaign scenarios.
While specifics of multiplayer haven't been revealed, Halo 4 will offer a "vast arsenal" of weapons, the return of medals, and familiar map features such as gravity lifts and man cannons.
Halo 4 will also offer a redesigned HUD and a game engine with visuals and sounds built entirely from the ground up.
"We really want to redefine that Halo multiplayer is, and make it so that it's something that's indisputably Halo at its core, but has evolved in important and innovative way," said creative director Josh Holmes at a press briefing attended by Digital Spy.
"From a gameplay standpoint it's really about creating something that's true to that magical Halo feel but is faster, more visceral and intense in all aspects of the combat."
Systems outside of matches will also be dramatically changed, and have been teased to be "unifying the surrounding experience for multiplayer and providing a new way for you and your friends that's unlike anything you've played before".
> Read our Halo 4 interview on multiplayer and narrative with 343 Industries
Also revealed was the campaign's redesigned Master Chief, which was given its first two images.
Halo 4 was unveiled at last summer's E3 in Los Angeles. The game will kick off a new Xbox 360 trilogy, following on from the events of Halo 3.
Extensive details about the sequel were revealed late last year, including the Forerunner-built setting, art direction and story.
Halo 4 will be available exclusively on Xbox 360 later this year.
Watch Halo 4's reveal trailer below: