If this was the Alien movie that Ridley Scott REALLY wanted to make, it looks SCARY.
The Alien movie already had the element of The Thing, a spooky powerful being lurking just around the corner. That is what seemed to make Alien scarier than Aliens. Alien was a horror movie. Aliens was a war movie.
I think we do see the space jockeys. The prometheusforum.net is chock full of possible plots. They have a cool shot-by-shot analysis of the trailer. I think the best comment was something along the lines of "People in closeup shots near organic-looking containers in Ridley Scott movies do not seem to be able talk about it over drinks at the club afterwards."
There are xenomorph-looking creatures in the preview trailers. They are called "Cuddles" on the forum.
It might be important to note that the buzz is that the planet where the action takes place is LV-223, not LV-426, the scene of the Alien and Aliens movie.
And yet, the trailers show, a giant ship, crashing, much like a crashed ship on LV-426. Also, there is a Space Jockey looking character and a Space Jockey control seat.
One might guess that the events of this movie set up Alien, when that might not actually be the case.
Since Prometheus seems to have killed off At The Mountains of Madness, which was to have been directed by Guillermo Del Toro, it would seem there is a Lovecraftean theme. But it appears from the previews that the move is not gross enough, to be Lovecraft.
http://io9.com/5908278/did-prometheus-kill-guillermo-del-toros-mountains-of-madness-movie
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