Last year's Call of Duty 4: Modern Warfare was more than just a great game. It took a series that made a name for itself under the rich tapestry of World War II and pushed it some 60 years into the future. The end result was a game that used the latest advances in weaponry, in a setting influenced by some of today's most tense conflicts, to produce an experience both stirring and refreshing. Since then, the big question on everyone's mind has been this: What will they do with the fifth Call of Duty? The answer, we know now, is a return to World War II. But rather than a step backward, Call of Duty: World at War is shaping up to be a unique take on this familiar timeline. With part of the campaign set in the often-overlooked Pacific theatre and plenty of inspiration drawn from Modern Warfare--both technical and creative--developer Treyarch is aiming to prove there's still life left in the World War II shooter.

　　Get ready for a darker narrative.

　　The most immediately apparent of the inspirations drawn from Modern Warfare is the mature, at times brutal form of storytelling. World at War begins with your character tied up in a hut on the beach of the Makin Atoll. A Japanese officer stands in front of you, demanding information from a fellow marine. An uncooperative spit to the face later, the officer puts his lit cigarette out on the face of this bound soldier and uses a knife to put a particularly bloody end to his suffering. But before you meet with a similar fate, backup arrives and you stage your escape. Pistol in hand, you're ready to begin World at War's first level.

　　After the first few minutes of fighting on the Makin beach, which offers some impressive visuals of exploding huts and moonlit ocean water, the squad of marines makes its way into the unknown of a nearby jungle. This is where the similarity to previous Call of Duty gains begins to wane. One of Treyarch's biggest areas of focus with the new Pacific setting is to portray the Imperial Japanese as soldiers very much unlike the Germans, the foils that have long served as the only enemies in the series. Rather than the obvious change in appearance and language, Treyarch has given the Japanese a starkly different set of tactics for you to deal with. Under the Bushido code, the Imperial Japanese fight with more of a focus on guerilla warfare. The first example of this is after your group has trekked through the dark jungle, past a collection of dead bodies. But in actuality, these Japanese soldiers are only pretending to be dead; they quickly pop up and attack your squad from behind. Another example of this take-no-prisoners tactical style in the first level includes Japanese snipers intentionally wounding a soldier so others come rushing to his aid, then taking out the group while they're distracted.

　　One of the tools you're given to combat these guerilla tactics is the use of fire-based weaponry, a trick displayed in the next level we were shown. Enemy soldiers often hide in the tall grass and dense foliage, even going so far as to climb up into trees for the perfect sniping opportunity. In this second level, the US marines are charging through more open terrain, this time during daylight hours. But despite the openness, patches of tall grass and palm trees dot the path to your goal. When your squad happens upon these areas of potential concern, you'll need to take a flame thrower and douse the greenery with blazing fire. Sometimes nothing is there, but occasionally you'll see charred enemies pop up from the grass, frantically waving and firing their guns with each last bit of life. Likewise, shooting fire at a tree might result in seeing a body fall from the branches, dangling from the rope he'd previously tied to his ankle as a safety harness.

　　Flamethrowers will play a big part in combat, with enemies frequently hiding in the grass.

　　Visually, this new form of weaponry really shows off some of the enhancements made to the impressive Call of Duty 4: Modern Warfare engine being used in World at War. Modern Warfare's engine was already known for its beauty and brains under the hood, displaying stunning visuals while accurately rendering the effects of ballistics traveling through myriad surface materials. But now there's an element of environmental destruction added to the mix. When torching grass, you'll see the fire slowly chew away the lush vegetation as the ground blackens beneath it. The rope keeping a dead body tied to a tree can be shot away. Planks making up the walls of beachside huts can be sawed away with bullets. And to add to all of this, Treyarch has taken it upon itself to give you the ability to swim, producing even more physics-related trickery like ripples from grenade explosions and bullets refracting when they strike the surface of the water.

　　This overarching goal of creating an altogether different World War II experience will carry over into multiplayer, as World at War will introduce a series first with co-op play. You'll be able to team up with friends with four-player online or two-player local connections. Treyarch is focusing on a natural stepping up in difficulty to compensate for the additional number of players. More than just increasing the hit points of enemies, the developer is working on ways to increase the size of battles and quality of enemy AI to provide a more challenging experience for your team of four. One of the big concerns we came away with is how it'll handle the dramatic, scripted moments that have become a series hallmark. It seemed to us like the teammate out in front would trigger these cinematic moments (planes crashing into view, enemies bursting out from hiding, and the like), while those dawdling behind would lose out on the Hollywood action. Treyarch, for its part, says this is a big area of focus in its testing process and it aims to have a solution when the game is released.

　　Competitive multiplayer, meanwhile, looks to be a bit more familiar. The system of persistent leveling and character perks used in Modern Warfare has been borrowed and enhanced with a number of new upgrades, like a flak jacket that helps protect you from grenade blasts. But not everything is strictly influenced by Modern Warfare. New to this game will be a squad system (a smaller group within the normal team) where spawns are highly influenced by where your squadmates are and cooperation is encouraged through a squad-only waypoint system. Vehicles will also make a return, though not the swift motorcycles and jeeps seen in Call of Duty 3. This time around the vehicle focus is on heavy-duty machinery like tanks and trucks. If Treyarch is able to pull off forming a cohesive experience out of all these elements and influences, the multiplayer experience should be quite the competitive powerhouse.

　　The ability to swim invites new potential for multiplayer mayhem.

　　While many shooter fans are understandably burned out on the World War II setting, the Pacific theatre section of the storyline is looking like an intriguing invitation back to the 1940s thanks to a palpable feeling of tension provided by the new focus on guerilla tactics. And the fact that they've adopted the wildly popular perk system from Modern Warfare's multiplayer system certainly doesn't hurt, either. We're looking forward to seeing how the rest of the campaign compares with the Pacific half. You can expect to see details on that front shortly. Call of Duty: World at War is scheduled for release later this year.