Update: Two new videos showing off Halo 4's gameplay along with a slew of new screens and game art have been released. Enjoy!

Original Story: Microsoft has opened their media briefing with a new look at Halo 4.

A live action trailer starts out with some looks at the story setup for the multiplayer experience, in which we see some bad things happening to the giant UNSC Infinity ship.

Cut to some in-game footage of Master Chief as he watches the Infinity crash down onto a mysterious planet. 

After the cinematic, the demo cuts to a first-person in-game perspective, and for the first time, we see Master Chief as he explores this strange new planet. Is this the Forerunner Shield World called Requiem, or some other strange world? It's not clear as Master Chief begins to move through a creepy jungle environment. Initially, some fights break out with Covenant forces, but within moments, we begin to see something entirely new.

For the first time, we get to see the long-promised new enemy type. The crawling creatures look like some sort of strange dog-insectoids that spit out energy projectiles. Shortly after, another enemy type begins to attack the Chief. The strange mechanoids appear to be utilizing Forerunner weaponry, and they exhibit a number of unusual behaviors that should offer some new challenges to players. From warping back and forth from point to point, to releasing robot drones from their own body that attack from the air, these creatures look like they should be quite the dangerous battle opponents. Are these some strange descendants of the original Forerunners, left here to evolve into savage mechanical creatures over 100,000 years? It remains to be seen, but one final sequence offers a sizzle reel of the some of the craziness awaiting in the rest of the game. including some shots of Cortana as she descends into madness and rampancy. 

Halo 4 will release on Xbox 360 on November 6. We'll have lots more about Halo 4 in the coming days of E3.