I'm not sure how to review this movie. If you already plan to see this movie but only know what you've seen in trailers then you might want to skip it. I'm trying to avoid spoilers, but there may be some hints you want to avoid.
I've known for a long time that it was a prequel to another science fiction horror movie. But that fact has been left out of the trailers and posters. By the end of the movie you'll have figured it out. Some logos, the artistic styling, these provide hints. But at the end there's a big hint and then a good whack on the head.
You don't need to have seen the other movies in this series to enjoy this one. This one stands on it's own quite nicely. But, a familiarity with the first movie does add an element to this one. But you can enjoy catching those references in your second viewing.
I find that an original movie has an advantage over later movies in the same series because the world we're being introduced to is new. Part of the movie is exploration and discovery. They have to come up with something extra to show the audience. The original Star Wars trilogy took us to at least three radically different worlds in each movie. New color schemes and environment so that even in the same movie there was always something new. "Promethius" has something new for people unfamiliar with the other movies, but people who know what they're walking into get something, too. They'll recognize a corpse from the original movie. And there are certain assumptions made about the corpse that will be challenged. Don't recognize him? Never mind. Even knowing what's coming you'll find a lot to discover.
Obviously, if you're not into science-fiction horror this isn't the movie for you. After seeing the trailers Yummy flat out refused to go. The movie isn't as scary as the trailers make it out to be. It's not as scary as the original. It's better lit than the original movie, but I'm wondering if that's because there's a 3D version which would have just been pitch black if it were as poorly lit as the original. There's one scene which I think would have made it worth the 3D, but even in 2D my eyes got big and part of me screamed "run".
I will be getting this and the sequel to the prequel on DVD. I may have to buy the original to go with it.