I remember seeing this film as a kid when my parents weren't watching and I must say, this is easily the scariest film of the modern era. The film is in the horror science fiction genre. The special effects and portrayal of the alien were terrifying, even for its time. It's the ultimate disaster flick where you're on edge, wondering when the alien will strike again and take out each protagonist as you helplessly watch the carnage unfold. Sigourney Weaver does a stellar performance of playing Ripley, who finds herself struggling to keep those around her alive amidst trying to protect herself. A great film!