The first 15 seconds look like they could be real-time. The rest looks pre-rendered.
I'm no modeling or animation expert, but the fact that there is visible geometry, flat ground textures, and frame rate dips in the first few scenes, then that all goes out the window for the thousands upon thousands of soldiers makes the real-time nature of the latter portion suspect.
This is still the only real Xbox 360 game I'm psyched for at this point, so I hope they can pull it off.
EDIT: Those first fifteen seconds aren't even Ninety Nine Nights? Oh well.