Preview - 'Halo 3: ODST'

Halo 3: ODST has had a few false starts since it was announced last year. Its E3 debut was pushed back by several months, back when it was called Halo 3 Recon, and was then billed as an expansion pack to fill the gap before the next Halo release. But Bungie being Bungie, it grew in size and scope, and with a new name and plethora of bonus material, it's all set for a full retail release come September. And it looks to be their biggest game to date.

Although technically part of the Halo trilogy (yes, they do usually come in threes), Master Chief is nowhere to be found. Set before the third chapter in the epic sci-fi drama, you play as The Rookie, an ODST member (Orbital Drop Shock Trooper) on a mission in the African city of New Mombasa, who becomes separated from his squad moments after departure. As you're no longer a Spartan, Bungie made a few sweeping changes to how the game controls.

"Duel-wield is gone, regenerating health is gone, motion-tracker is gone, falling damage is back. He's not as powerful as a Spartan, so taking away some of those things helped us achieve that goal," said Lars Bakken, Multiplayer Designer at Bungie. Although he's not as sharp or well-equipped as the Chief, that's not to say there's some compensation, such as a visor: "The visor is extremely effective, just because of its target acquisition mode, where you can see the enemies ringed in red, which is super helpful. You can see them long before they see you."

As you'll be exploring the city in pitch-black darkness, the visor becomes essential in highlighting enemies, friendlies and items with different colours. The structure of the campaign is entirely different, with no linear levels to follow, just an expansive, destroyed and deserted city with scattered clues to your squad's disappearance. Aided by an AI construct called the Superintendent, points of interest to investigate are plotted on the visor. As you are more vulnerable than ever before, rushing at Covenant sentries posted at every corner will get you killed. Sneaking and pulling off headshots with the silenced weapons, including a super-satisfying zoomed pistol that can fire as fast as you can pull the trigger, pays dividends.

The clues you'll discover are flashback mechanisms, allowing you to play as the squadmates on their last known missions in the city, providing more information of what happened to them. One clue was a bomb detonator, which plants you in the shoes of an ODST called Dutch. His mission is to set charges on a bridge while weaving between Covenant bombing raids, before climbing a tower and blowing the place to smithereens. "Some of them are on the same length as a Halo 3 mission, some of them are shorter, it just depends on the flashback itself," said Bakken.

They provide a welcome change from the tactical, slow-paced exploration of the city, and play more like the linear campaign missions from earlier Halo games. A big difference is that they can be tackled in any order: "Originally when we were developing the game we would just drop you in," explained Bakken, "with the entire city open to you, but we found that was way too much for people. Now in the game in the beginning you start on a more narrow path, play the first couple missions in the same order, then we open up the city and you play as you see fit."

The expansive city promises to house more than just clues, with Bakken teasing lots of other things to occupy your time. "The city of New Mombasa is really big. People are going to spend a lot of time in that city because there are things in there that we can't talking about yet." Bungie is keeping tight-lipped about its secrets - we do know that achievements will come into it - and about the number of flashbacks. Without exploration, Bakken said "it might be a little shorter than Halo 3" when played from start to finish, but with four-player co-op, campaign scoring and skulls, not to mention those extra-curricular activities we aren't privy to, it should make for Halo's most interesting campaigns to date.

Outside of creating New Mombasa, Bungie has been hard at work on a new co-operative mode. Like Terrorist Hunt and Horde from Rainbow Six and Gears Of War, Firefight drops you in an arena against relentless numbers of Covenant with limited resources to fight them off with. Sharing a pool of lives between your team, enemies grow in size and number with each progressing wave, with skulls turned on at regular intervals to pile on the pressure. Matches can last forever provided you stay alive, and although scoring, medals and friend leaderboards add a competitive edge to proceedings, the lack of motion-tracker means co-operation and communication becomes essential.

"One of the things that makes Firefight different is that it's in the Halo universe and that it's in the Halo sandbox," said Bakken. "You've got access to every single weapon and access to all the vehicles, including Warthogs that you can drive around in." Halo's lack of cover mechanic makes Firefight a more open and tense affair than its peers, with maps designed to stretch your resources in different ways. Alpha Site is a column-filled floor with two designated drop points for enemies which quickly fan out and flank you; Security Zone is an expansive dirt bowl with turrets and Wraiths propping up the corners, and Crater is a pitch-black city district that requires the Visor to see, giving off a unique neon vibe.

Firefight looks to marry the celebrated campaign and multiplayer sides of Halo together perfectly, but it won't turn its back on its ever-popular online matchmaking. ODST will come with a dedicated disc housing all the file-sharing and maps from Halo 3, complete with three new ones, all compatible with existing online players. As it won't include any new weapons or features from ODST, it's a smart way of allowing newcomers to jump online without barriers. Although Bungie said this will be the last set of maps for Halo 3, Brakken insisted they don't see "support for matchmaking dying off anytime soon", with plenty more playlist ideas up their sleeves.

And if that wasn't enough, Halo 3 ODST comes with access to the Halo: Reach beta, Bungie's last foray with the series. With a radically different campaign structure that takes the narrative and level design to new heights, and a host of robust multiplayer features in Firefight and the bonus multiplayer disc, it'll be an appropriate end to a trilogy that has changed the first-person landscape forever. While it had a tenuous start, it certainly looks like those growing pains will pay off.

Halo 3 ODST will be available on Xbox 360 on September 22.