For its first four installments, the Alienfranchise was most concerned with offering up a combination of horror and sci-fi action, and less concerned with delving into lore. Prometheus, however, goes in a different direction, and Scott uses the prequel to explain the origin of the Xenomorphs and the Engineers. Though the film earned generally positive reviews and has a 73% score on Rotten Tomatoes, these explanations demystified the franchise, a move that, in addition to a focus on David (Michael Fassbender), an android, proved controversial.
I’m in the minority, but I like the lore provided by Prometheus and the movie.
The Alien movies didn’t come across as mystique to me rather that they left me hanging too much on a lot of background.