In Gameinfomers issue It stated the Story takes place right after Aliens you and your squad of marines are to investigate the Sulaco and to find out why the Marines from the film never contacted you and what happened at LV-426. They mentioned that fans of the first Alien Film will be pleased because the space Jockey will be part of the game. The developers are also trying to have very interesting characters that are similar from the film .
Note on game play I thought it was a good idea that they will have the smooth head Aliens to be more stealthy then the warrior Aliens. Since the developers do not want certain Aliens to be stronger. The game will have Co-Op. offline up to two player CO-Op and online will feature four player CO-Op. No word on the multiplayer game modes yet. But it would be nice to have the mode survivor from AVP2.
This game sounds like a dream come true to me and I have very high hopes not only for what I have just posted but because the game is being made by real developers which is GearBox.
Sorry if I posted any incorrect info and bad grammar.