New Halo 3 trailer, details

It's official - Halo 3 is on the way and will be hitting the shelves some time next year. But you can see it in action right now, because the trailer shown at Microsoft's press conference is available for viewing on Eurogamer TV.

According to Bungie's website, the trailer is very much running in real time, and it's designed simply to give us a sneak peek at the graphics and audio - they're keeping the multiplayer modes and all the other exciting stuff under wraps for now.

However, it does also reveal the return of Cortana, which director of cinematics CJ Cowan says will be key to the plot. "Cortana and the Chief being a galaxy apart is a situation we haven't seen before, and is something that is a powerful component to Halo 3.

"We are using her transmissions in the demo to give the viewer a few subtle clues to her situation and state of mind, without revealing any specifics we want to save for the game itself."

But Cortana's by no means the game's biggest star, as Cowan observed: "It is the Chief, back on a devastated and Covenant controlled Earth, standing over the excavation of a structure buried in the crust of our own planet that is the meat of our demo.

"The questions raised by these images, and the feeling that our assumptions about the Halo universe are being challenged this late in the story is what I am personally most excited about leaving with our fans. That's the type of thing that builds anticipation even more for the payoff to this trilogy we are preparing."