Creative Assembly seems to be going for the Amnesia/Outlast type of feel with Alien: Isolation making it a more survival horror game rather than the action games that the past few Aliens games exhibited.
To help generate that feeling of dread, the team is trying to make the Alien reactive rather than scripted. Once you figure out a pattern for a creature, it becomes less terrifying. Creative Assembly hopes to have an organic experience when coming up against the creature and it's definitely one that you want to stay away from.
The footage, which from past experiences you shouldn't take as final, exhibit some great atmosphere and if it's any indication of the final product, really captures eerie feeling that something, somewhere is stalking you in this very scary place.