One of my top three favorites of all time.

Rating: 9/10 (1 October 2004)

Let me start off by saying this is a great movie. The setting, the characters, the creature itself, are all superb. It takes awhile to get into the true horror element of movies, but when the film does, it is a visceral experience.
It starts off when a Company (Weylan-Yutani/Weyland-Yutani in Aliens) spaceship is rerouted to intercept a transmission of unknown origin. When the crew sets off to investigate on the planets surface, they bring back an organism that is absolutely lethal when it encounters humans. It soon wreaks havoc on the ships crew picking them off one by one.
Whereas the sequel to the movie, Aliens is the favored movie out of all the Alien films, I feel that it just doesn't have the air of mystery around it like the original does. In Aliens we discover that the creature needs a Queen to further its lifecycle, whereas in Alien some of the horror came from not knowing what it was doing to the crew.
The film is shot pretty darkly to show the double-sided feature of man's technology. The ship goes from brightly lit and futuristic when the crew wakes up, to dark and spooky when they set off to look for the Alien in the Nostromo's underbelly.
What makes this film succeed in my opinion is that the creators of the film decided to throw in your average human beings into the mix. There is nothing superpowerful or outstanding about them, they are just your average joe, like all the other average blue collar folks out there. They are afraid, doubtful, and panic stricken yet always have hope that they can make it out of the ship alive. Just like 90% of the people without military experience that get stuck in horrible situations. These "space truckers" must find a way to defeat a seemingly unstoppable and stealthlike creature that is born to kill.
The set designs, sound and visual effects are all a bonus to a movie that I feel has dated extremely well over the last few years.
If you haven't seen one of the horror movies that helped define the sci/fi-horror genre, then perhaps you should go rent it as quick as possible.
9.5/10