The movie opens when the crew is awoken unexpectedly from their hyper-sleep by the ship’s computer called “Mother”. The ship has received a signal – assumed to be an SOS – from a nearby planet. This signal must be investigated under their company contract, and the crew reluctantly land on the planet to find its source.

They soon realise that there is something very wrong; they discover a long-destroyed alien ship, a long-dead crew-member, and strange eggs hidden underneath. One of these eggs releases a creature that attaches itself to Kane’s face. After they rush him back to the ship and break protocol by bringing him on-board, the creature starts to prove much more menacing than anyone had imagined.

Unlike many modern science-fiction films, this movie uses a slow, almost crawling, pace at first and builds up tension to create a realistic, immersive thriller experience.

“One of the great strengths of "Alien" is its pacing. It takes its time. It waits. It allows silences (the majestic opening shots are underscored by Jerry Goldsmith with scarcely audible, far-off metallic chatterings). It suggests the enormity of the crew's discovery by building up to it with small steps,” says Roger Ebert in his own review.

In addition to the creature which is iconic in all its incarnations: the egg, the “face-hugger”, the “chest-buster”, and of course, the full-grown Alien – there are also many sequences from the movie that rank among the most memorable moments in movie history – celebrated especially by sci-fi fans all around the world. For anyone intending to watch the film however, these scenes are best left unspoiled by prior description.

The special effects in this movie will leave you stunned about the fact that it was made in 1979. A combination of realistic, painstaking designs and minimalist techniques in sound and camera leave an impact that achieves much more than complicated CGI effects and techniques often overused today. The claustrophobic mining ship, the cold, desolate planet, and the eerie Alien wreckage are just a few of the well-rendered elements that make you forget that it is an “old” movie.

The realism in the film was a special undertaking of writer Dan O’Bannon, who, after making a comedy alien-flick where the creature was crafted out of a beach ball, was left with the desire to “.. do an alien that looked real.”

The casting too, was “realistic”. Rather than have a group of savvy space-explorers, or young soldiers on the ship, this movie shows us a crew of miners and wage-earners who are older than your average sci-fi action cast, and are also quite reluctant to get into any action at all.

The casting of Sigourney Weaver as the lead in such an action-intensive, sci-fi film was also groundbreaking. She is no hapless beauty running from a monster. She played the role beautifully, never letting us doubt that she is every bit the tough, improvising hero that any man could be. At the same time, she portrays a unique intuition and decision-making instinct that leaves us in no doubt about her femininity.

“Alien” has of course, spawned a huge franchise that is still active today – which includes not just three other sequels, but also collectibles, games, comics and cross-overs of all sorts. The movie is voted second in IMDB’s top horror movies of all time, and sixth in sci-fi.

Of its sequels, "Aliens", directed by James Cameron and released in 1986, was a major box office hit and also won two Academy Awards while "Alien 3" and "Alien Resurrection" enjoyed varying degrees of success and acclaim. But for anyone who either enjoys a great horror, or sci-fi film, the original is definitely a must-watch.

If you are revisiting this movie, or seeing it for the first time – watch the 2003 Director’s Cut version: