"Yeah, it surprised us too," Call of Duty: Black Ops multiplayer design director David Vonderhaar told us at the multiplayer reveal event in Los Angeles earlier this week. What surprised Vonderhaar and the team at Treyarch was the "30 to 40 percent" of Call of Duty players that never venture into mulitplayer, according to Activision research. His goal for Black Ops: To get as many of those people into multiplayer as possible.

With Modern Warfare 2 breaking sales records and its developer, Infinity Ward, in a state of collapse, following the highly publicized departure of the studio's founders and many of its senior staff, all eyes are on Treyarch to pick up the torch and deliver the most robust and polished multiplayer experience the franchise has seen yet.

But how far does Vonderhaar look to find competition? "The benchmark is always the last game that the studio's made, or that Activision's published," he said. "Multiplayer CoD games command three of the four top spots on Xbox Live right now. We're filling stadiums of people every night with players." And that fan base, which is shared across Infinity Ward's two Modern Warfare titles along with Treyarch's zombie-infused World at War multiplayer, hasn't shied away from upgrading annually.

But first, there's a challenge that Vonderhaar notes: A lot of different kinds of gamers buy Call of Duty games and never go online.