There are only two things you need to know about Ridley Scott's slasher-movie-in-space masterpiece: firstly, it's one of the greatest sci-fi movies ever made. And secondly, it's a completely different beast from James Cameron's pumped up Vietnam-in-space sequel.

"BARELY DIFFERENT"

Released to celebrate Alien's 24th birthday, this version of the film about a creature killing the crew of a spaceship one by one is barely different from the original. A director's "cut" in the literal sense of the term, this trims a minute off the original movie's running time.

While restoring a few deleted scenes such as Ripley (Sigourney Weaver) and Dallas (Tom Skerritt) arguing about the ship's quarantine procedures, Scott also throws in a few sequences in the medical lab, and the moment Ripley discovers the cocooned remains of her former crewmates.

But what really makes this worthwhile is the chance to see Scott's imposing vision in all its 70mm glory. The digitally remastered print is also accompanied by an eardrum-perforating new stereo mix.

"JAWS PLUMMETING TO THE FLOOR"

As the hull of the Nostromo sails across the cinema screen, or the crew enter the wreckage of the gigantic alien vessel that houses a cargo of deadly eggs, the scale of Scott's film can't fail to leave jaws plummeting to the floor.

Cameron's sequel may have surpassed Scott's film in terms of balls-to-the-wall action, but it's the original that lays down the seeds of the Alien mythology, obsessively toying with themes of birth, motherhood and sex in quite outrageous ways.

At the same time it reworks the sexual anxiety of the slasher movie with startling efficiency. Tick off the Freudian nightmares that include the phallic-shaped xenomorph, the android Ash (Ian Holm) erupting in a creamy white mess, or the womb-like control room of the ship's onboard computer (appropriately named 'Mother'). And then there's the scene in which Ash tries to kill Ripley by stuffing a rolled up porn mag down her throat.

"INTELLIGENT, ADULT AND UNSETTLING"

Scott has always claimed it's nothing more than a dumb monster movie, but Alien is clearly much more than that. Arriving only two years after the family friendly space operatics of Star Wars (1977), this is a seminal example of science fiction cinema at its most intelligent, adult and unsettling.

Alien: The Director's Cut is released in UK cinemas on Friday 31st October 2003.