Unfortunately you aren’t allowed to take footage of the demo being show of Colonial Marines at E3 but written previews of the demo are starting to come out:
“In a live gameplay demo, we got a chance to see many familiar elements from the movie. It opens with a ship crashing onto the surface of LB-426. The player comes to with a fellow Marine asking if he’s all right. The response is a quick middle finger.
The Marines start sweeping the area, walking through the medical bay with tubes of facehuggers suspended in fluid. A tracker starts pinging its familiar sound, though it doesn’t detect anything. For now. After a few moments, the squad comes upon a reinforced steel door that’s been torn open by something with obvious strength. After walking into a ruined operations area, a member of the squad screams as a xenomorph tears through the ceiling and attacks.”
I’ve left the error in regarding the title of LV426. That is part of Game Informer’s preview. Others include: MTV Multiplayer, GameRevolver, ComingSoon and GameSpot. The previews all speak of a new variant of Alien too. Thanks to Newbeing, Xeno and Chris.