The over 10 minute clip includes talks from artists, designers, writers and producers on Halo 4. It's the very first adventure for Master Chief outside of original creator Bungie as 343 carry the torch.
Apparently fan-made multiplayer mode 'Grifball' will also be available in Halo 4 as it is set to become official. Halo 4 releases exclusively on Xbox 360 November 6th.