The Call of Duty franchise is currently the best-selling series on the Xbox 360, and it's also well up there on the PlayStation 3, thanks to last year's Modern Warfare 2. The series has attracted a lot of fan attention due to the firing of the heads of MW2 developer Infinity Ward and their subsequent signing on with EA Partners as Respawn Entertainment. In the meantime, Activision's Treyarch, who was responsible for 2008's Call of Duty: World at War, has been puttering away at a new entry. Treyarch showed off Call of Duty: Black Ops at E3 2010 to small audiences in a private room.

The demonstration starts on an aircraft carrier in the Pacific Ocean. With a few basic action commands, the player starts up the jet and pilots it to the skies over Russia. We get a detailed view of what's going on below, where a few U.S. soldiers are hiding behind a rock. Gameplay becomes a real-time strategy, with the pilot pointing out places and telling the team to go down. It's clear that this sequence forces the team to a specific location on a hill not too far away, where gameplay switches viewpoints to one of the soldiers you were just commanding down below, and the series' more typical gameplay begins.

The gameplay immediately shifts to something more familiar. The guns are more in line with the modern entries of Modern Warfare 2 but are appropriate to the time, so there won't be any high-tech prototypes. As the team goes toward a road by climbing the hill, the team reaches a railing and hooks onto it to rappel down. This is handled as yet another minigame of glorified action commands, ending when the player reaches the right spot to jump and kick through a window. They can start shooting before then, potentially taking out the enemies within before even entering the room.

The remainder of the map includes surprises such as an avalanche, and a few points when the player has an active choice of stealth or opening fire. As the team completes their mission, the Treyarch reps pointed out that this mission takes place during the Vietnam War, but in Russia. The heroes are a Special Forces team, taking on one of the titular "Black Ops" — missions that can't be traced to America if they fail or are noticed. They clarified that the game is not all about the Vietnam War as initially indicated, but where the timing goes from there is still a mystery.

Without providing too much detail about the location, the scene changes to a few remaining soldiers, who are apparently escaping after being captured and are on their way to board an enemy helicopter. The Treyarch rep indicated that this did not involve a control change and uses the typical control scheme so that the player can focus on the action. The player opens fire on various village encampments and locations, and the scene quickly collapses into an orgy of destruction. With no apparent ammunition limits, the only challenge is the occasional soldier with an RPG and a few enemy helicopters.

Call of Duty: Black Ops shows that Treyarch has been learning, but it's difficult to tell if they've topped Infinity Ward's magnum opus with this effort. The Treyarch reps also noted that the timed exclusivity for maps on the Xbox 360 will persist until at least 2012.