The narrative brilliance I speak of is Scott's long-winded desire to make Ripley (Sigourney Weaver) the eventual hero of the film... and the franchise face. Sure, there had been women heroes before whose quest for survival derived from their victim status (rape to revenge or assault the system by crime), but here was a woman hero who outlasts the danger and actually kicks ass on her accord. Upon original release, I'm sure untrained eyes were just waiting for Tom Skerritt or Yaphet Kotto to retaliate against the evil alien life form. But they were just pawns on the board, disappearing in order and timed to a screeching soundtrack that seemed to propel the alien forward. Also, besides the now infamous John Hurt stomach emergence scene, I was quite taken aback how bloodless "Alien" works. Unlike the future installments, "Alien" gets its point across through unsettling lighting, quick cuts of protruding alien tongues and, my favorite, death through the eyes of a cat.
I don't know how good "Prometheus" will be, as early reviews are diving the critics, but one can always return to the original greatness of the "Alien" franchise and relish the moments that created such a terrific series of films... and broke some genre ground in the process.