Alien (1979)

Ridley Scott's original vision to his sci-fi masterpiece, Alien, was bleak, but true to the film in the sense that it was absolutely horrifying. Instead of Ripley (Sigourney Weaver) shuttling out of the Nostromo and casting her alien intruder out into the deadly cold vastness of space, Scott had the alien kill Ripley by ripping her head off and then mimicking her voice over the radio to communicate with Earth.