LOS ANGELES — Vince Zampella is back at E3.

After spending the past three years engaged in both legal battles and work on a new game, the "Call of Duty: Modern Warfare" co-creator has returned to the Electronic Entertainment Expo to debut "Titanfall," the first title from Respawn Entertainment, the studio he launched with partner Jason West after they were fired by Activision-Blizzard Inc. in 2010.

"This development for 'Titanfall' has been rough," he acknowledged Wednesday at the booth of Electronic Arts Inc. "We started a new studio. We had no technology. We had no ideas. It was a team of hugely talented developers put together in a room — very strong and outspoken — who all want their idea to come to forefront. It's a battle of what idea is the best."

Ultimately, that idea turned out to be a shoot-'em-up multiplayer game where players portray futuristic soldiers who can run up walls and man giant robots dubbed titans. (The name "Titanfall" refers to the moment they dramatically fall from the sky when players call them.) Unlike previous games he's worked on, "Titanfall" is an online-only experience.

Zampella closed out Microsoft's presentation Monday by debuting "Titanfall" for the first time. The game is set for release next year for Microsoft's next-generation Xbox One console, as well as the current-generation Xbox 360 and PC. He noted that Xbox One's cloud computing capabilities will make for stronger artificial intelligence in the game.

"It's not bots," said Zampella. "It doesn't replace the human element. It puts in this extra layer of believability. It brings the world to life. We do that on the cloud. There's no host advantage. It's a very balanced experience. It allows us to focus on rendering abilities on the box itself and host the game on the cloud."