The world premiere of Alien entailed an enormous cataclysm in the science-fiction cinematographic genre.
Generally speaking, Alien is a classic terror film, staged in a very advanced technological future, enormously credible through the use of very skillful technical ability.
        

The film script ( from a novel by Dan O´Bannon and Ronald Shusett) lets the director Ridley Scott, the cameraman Derek Vanlit and the composer Jerry Goldsmith drive the relentless emotions of endless visual surprises (and horrors).
        

Already in itself, the plot offers subtle paralellisms with It!, The Terror from Beyond Space, The Thing from Another World ( Dir: Christian Nyby, 1951), The War of the Worlds (Dir: Byron Haskin, 1953), Invasion of the Body Snatchers (Dir: Don Siegel, 1956), Quatermass and the Pit (Dir: Roy Ward Baker, 1968), etc.
        

In contrast to the life in outer space, full of glamour and adventure, often represented in science-fiction films, Alien shows initially a mundane and boring cargo spaceship, with some of the crew members like the rude Yaphet Kotto, constantly complaining about their wages and work conditions. This situation is shared by the captain (Tom Skerrit), his assistant the lieutenant Ripley (Sigourney Weaver) and the rest of the crew, performed by a good casting of actors and actresses.
        

The film won the Oscar to Best Visual Effects in 1979 and with this great production we get into science-fiction combined with elements of the most classical terror films:a group of persons within a closed environment,with a lethally killer and almost invisible alien between them, everybody being inside a commercial cargo spaceship.
        

The hair-raising extraterrestial alien is a creature going on quickly increasing its size and enters the spaceship adhered to the space suit helmet of one of the passengers (John Hurt), after a forced landing on an uninhabited planet to investigate a SOS call from another spaceship, whose crew members of grotesque and terrible look are all dead, but not some mysterious big size throbbing eggs that they discover in the surrounding area.

Precisely one of them opens when one of the human beings is by it and it adheres to his face, being taken on board of the cargo spaceship ´Nostromo´.
        

Then, on the operating table, the fierce baby monster spouts violently from the chest of the patient holding it, and from that precise instant, the monster is growing up more and more at a dizzy pace, revealing himself implacable.
        

The thrill reaches unimaginable peaks, with phases of unbearable tension preceding the systematic extermination of the spaceship occupants, one after the other.
Paradoxically, the spaceship often becomes gigantic in the spectator mind, because Alien can attack from any point of it and at any moment.
        

Specially remarkable was the design of the alien spaceship appearing in the beginning of the film, by the artist H. R. Giger, returning to the beginning of German cinema influence (an artist of the odd and strange creating the fantastic one) and it worked wonderfully.
        

Alien represents the terrorific aspect of an extraterrestial monster with great size, strength, speed and intelligence, lacking feelings, ethics or margin for piety. It is an essentially hostile and naturally lethal entity.
        

The genesis of this concept, although with greater morphological human affinities starts from the mythic 1920 German silent movie ´Algol´, in which an alien from the star Algol arrives at the Earth with a huge machine conferring him enormous powers, making a great havoc, while great peaks of verosimilitude are reached thanks to the extraordinary settings by Paul Sheerbat and Walther Reimann, with Emil Jennings playing the role of Mephisto, the Alien coming from Algol.
        

But Alien doesn´t need any machine at all. It itself is a devastating and invulnerable killing machine. In fact, within the spaceship travels as an insider spy, along with the rest of the passengers, an android charged with trying to wreck any attempt to eliminate Alien and on being discovered, he will reveal them that everything has been decided and thought in advance: everybody is going to die and they won´t be able to do nothing against the lethal alien, which uses the spaceship ventilation conducts to move.

Alien will go on progressively and inexorably eliminating the human voyagers, and the feeling of impotence and defenselessness before its surprise is big at every moment.

It is an entity from another world, very evolved and almost indestructible, and its defense capacity is such that it is made up by an unknown molecular acid, springing up from its body when it is hurt, destroying everything it touches or perforating on contact the different floors of the spaceship!
Some parallelisms have been established with the Nietzschean ontology and the dynamics of power will in this extraterrestial creature, not affected at all by any doubt of ethical nature, although its lack of absorption in thought or own introspection (in line with Ortega y Gasset´s thesis in his work ´En Torno a Galileo´) is perhaps the feature establishing more differences, since Alien is basically an evolutive survivor and a formidable biological mechanism of attack and autodefense in any biotype. Its basic premise is to subsist and the anxieties for profit and power do emanate preferently from the unscrupulous minds of the ´Nostromo´ commercial cargo spaceship entrepreneurs, who try to get a possible military, commercial and genetic engineering gain, capturing the destructive alien and not doubting on sending the human beings to a sure death.
To the omnipresent uncertainty factor contributes the fact that ´Mother´, the very powerful central computer on board, can´t offer any data on the Alien features, because human science doesn´t know anything similar to it.
Both the special effects and the musical score by Jerry Goldsmith are really gorgeous.

There are very remarkable Hitchcock-like effects hits, in punctual moments, adding more stress, above all with the sudden frights brought about by the appearance of the little cat ´Jossie´ .
        

The wondrous shots of the ´Nostromo´ spaceship, from different angles, are very famous.
It is also remarkable the outstandingly original progressive insertion of the letters ALIEN with the unknown planet in the background, at the beginning of the film along with the sound effects, smoke, vapours, etc, of the spaceship ´Nostromo´, Programmed for its final explosion and autodestruction by lieutenant Ripley.
        

Ridley Scott reveals himself recurrent in the nightmare, for Ripley (Sigourney Weaver) thinks that she has been successful in abandoning the spaceship on the new little auxiliary airship, leaving his dead comrades and Alien in ´Nostromo´, but as a matter of fact, the alien has managed to escape and it is with her inside the new little aircraft, beginning a ruthless war between the lieutenent Ripley and the bloody alien, which is finally destroyed and hurled drift into the outer space.

        

To a large extent, Alien inspired the film director John McTiernan in Predator (1987), also with a deadly Alien attacking with impressive speed and strength, albeit in the context of a fully earthly tropical jungle and with several special effects whose constant epicenter is the use of the ´thermic vision shots´ by the photography director Donald Alpine.