The success of Alien led 20th Century Fox to finance three direct sequels over the next eighteen years, each by different writers and directors. Sigourney Weaver remained the only recurring actor through all four films, and the story of her character Ripley's encounters with the Aliens became the thematic thread running through the series. James Cameron's Aliens (1986) focused more on action and involved Ripley returning to the planetoid accompanied by marines to confront hordes of Aliens. David Fincher's Alien 3 (1992) had nihilistic tones and found her on a prison planet battling another Alien, ultimately sacrificing herself to prevent her employers from acquiring the creatures. Jean-Pierre Jeunet's Alien Resurrection (1997) saw Ripley resurrected through cloning to battle more Aliens even further in the future.
The success of the film series resulted in the creation of a media franchise with numerous novels, comic books, video games, toys, and other media and merchandise appearing over the years. A number of these began appearing under the Alien vs. Predator crossover imprint, which brought the Alien creatures together with the titular Predators of the Predator franchise. The film series eventually followed suit, with Paul W. S. Anderson's Alien vs. Predator (2004) and Colin and Greg Strause's Aliens vs. Predator: Requiem (2007) These stories are set in the 2000s.
Sigourney Weaver has expressed interest in reuniting with Ridley Scott to revive her character for another Alien film. In the 2003 commentary track for the Alien DVD included in the Alien Quadrilogy set, she and Scott both speculated on the possibility, with Weaver stating: "There is an appetite for a fifth one, which is something I never expected...it's really hard to come up with a fifth story that's new and fresh...but I have wanted to go back into space...I think outer space adventure is a good thing for us right now, 'cause Earth is so grim...so we've been talking about it, but very generally." Scott remarked that, if the series were to continue, the most logical course would be to explore the origins of the space jockey and the Aliens. Weaver supported this idea, stating that "I think it would be great to go back, because I'm asked that question so many times: 'Where did the Alien come from?' People really want to know in a very visceral way." David Giler stated that he, Walter Hill, and Gordon Carroll, the producers of the first four films in the series, would not be willing to produce another unless it was about the Aliens' homeworld and Weaver was on board (although they were among the producers of Aliens vs. Predator and its sequel). Weaver, in turn, indicated that she would only return to the franchise if either Scott or James Cameron were directing. Cameron had been working on a story for a fifth Alien film which would explore the origins of the creatures, but ceased work on it when he learned that Fox was pursuing Alien vs. Predator, which he felt would "kill the validity of the franchise". Weaver has continued to express interest in another installment, stating in 2008 that "I would definitely do another if I had a director like Ridley Scott and we had a good idea. Ridley is enthusiastic about it."
In July 2009, 20th Century Fox announced that Jon Spaihts had been hired to write a prequel to Alien, with Scott attached to direct. The script was subsequently re-worked by Scott and Damon Lindelof. Titled Prometheus, it went into production in May 2011, and was subsequently released in 2012. Scott released a statement: "While Alien was indeed the jumping-off point for this project, out of the creative process evolved a new, grand mythology and universe in which this original story takes place. The keen fan will recognize strands of Alien's DNA, so to speak, but the ideas tackled in this film are unique, large and provocative."
Variety reported on February 18, 2015 that a new Alien film will be directed by Neill Blomkamp. On February 25, it was confirmed that Sigourney Weaver would have a role in the film.
"The 1979 Alien is a much more cerebral movie than its sequels, with the characters (and the audience) genuinely engaged in curiosity about this weirdest of lifeforms...Unfortunately, the films it influenced studied its thrills but not its thinking."—Film critic Roger Ebert on Alien 's cinematic impact.
Alien had both an immediate and long-term impact on the science fiction and horror genres. Shortly after its debut, Dan O'Bannon was sued by another writer named Jack Hammer for allegedly plagiarising a script entitled Black Space. However, O'Bannon was able to prove that he had written his Alien script first. In the wake of Alien's success a number of other filmmakers imitated or adapted some of its elements, sometimes by copying its title. One of the first was The Alien Dead (1979), which was titled at the last minute to cash in on Alien's popularity. Contamination (1980) was initially going to be titled Alien 2 until 20th Century Fox's lawyers contacted writer/director Luigi Cozzi and made him change it, and it built on press coverage of Alien's chestburster scene by having many similar creatures, which originated from large, slimy eggs, bursting from characters' chests. An unauthorized sequel to Alien, titled Alien Terror (originally Alien 2: On Earth), was released in 1980 and included alien creatures which incubate inside human hosts. Other science fiction films of the time that borrowed elements from Alien include Inseminoid (1981) and Xtro (1982).
The film studio The Asylum has produced two mockbuster based on the Alien franchise: AVH: Alien vs. Hunter (based on the crossover Alien vs. Predator: Requiem) and Alien Origin (based on Prometheus).
Critics have analyzed Alien's sexual overtones. Following Barbara Creed's analysis of the Alien creature as a representation of the "monstrous-feminine as archaic mother," Ximena Gallardo C. and C. Jason Smith compared the facehugger's attack on Kane to a male rape and the chestburster scene to a form of violent birth, noting that the Alien's phallic head and method of killing the crew members add to the sexual imagery. Dan O'Bannon has argued that the scene is a metaphor for the male fear of penetration, and that the "oral invasion" of Kane by the facehugger functions as "payback" for the many horror films in which sexually vulnerable women are attacked by male monsters. McIntee claims that "Alien is a rape movie as much as Straw Dogs (1971) or I Spit on Your Grave (1978), or The Accused (1988). On one level it's about an intriguing alien threat. On one level it's about parasitism and disease. And on the level that was most important to the writers and director, it's about sex, and reproduction by non-consensual means. And it's about this happening to a man." He notes how the film plays on men's fear and misunderstanding of pregnancy and childbirth, while also giving women a glimpse into these fears. Film analyst Lina Badley has written that the Alien's design, with strong Freudian sexual undertones, multiple phallic symbols, and overall feminine figure, provides an androgynous image conforming to archetypal mappings and imageries in horror films that often redraw gender lines. O'Bannon himself later described the sexual imagery in Alien as overt and intentional: "One thing that people are all disturbed about is sex... I said 'That's how I'm going to attack the audience; I'm going to attack them sexually. And I'm not going to go after the women in the audience, I'm going to attack the men. I am going to put in every image I can think of to make the men in the audience cross their legs. Homosexual oral rape, birth. The thing lays its eggs down your throat, the whole number.'"
In the decades since its original release critics have analyzed and acknowledged Alien's roots in earlier works of fiction. It has been noted as sharing thematic similarities with earlier science fiction films such as The Thing from Another World (1951) and It! The Terror from Beyond Space (1958) as well as a kinship with other 1970s horror films such as Jaws (1975) and Halloween (1978). Literary connections have also been suggested, including thematic comparisons to And Then There Were None (1939). Many critics have also suggested that the film derives in part from A. E. van Vogt's The Voyage of the Space Beagle (1950), particularly the stories "The Black Destroyer", in which a cat-like alien infiltrates the ship and hunts the crew, and "Discord in Scarlet", in which an alien implants parasitic eggs inside crew members which then hatch and eat their way out. O'Bannon, however, denies that this was a source of his inspiration for Alien's story. Van Vogt initiated a lawsuit against 20th Century Fox over the similarities, but Fox settled out of court. Rick Sanchez of ign.com noted the "striking resemblance" to Mario Bava's cult classic Planet of the Vampires (1965), especially in a celebrated sequence in which the crew discovers a ruin containing the skeletal remains of long dead giant beings, and in the design and shots of the ship itself, similar to the derelict spacecraft in Alien. Despite the visual similarities, both O'Bannon and director Ridley Scott claimed in a 1979 interview that they had not seen Planet of the Vampires.
Writer David McIntee has also noted similarities to the Doctor Who episode "The Ark in Space" (1975), in which an insectoid queen alien lays larvae inside humans which later eat their way out, a life cycle inspired by that of the ichneumon wasp. He has also noted similarities between the first half of the film, particularly in early versions of the script, to H.P. Lovecraft's At the Mountains of Madness, "not in storyline, but in dread-building mystery", and calls the finished film "the best Lovecraftian movie ever made, without being a Lovecraft adaptation", due to its similarities in tone and atmosphere to Lovecraft's works. In 2009, Dan O'Bannon said the film was "strongly influenced, tone-wise, by Lovecraft, and one of the things it proved is that you can't adapt Lovecraft effectively without an extremely strong visual style ... What you need is a cinematic equivalent of Lovecraft's prose." Regarding O'Bannon's initial Alien storyline, H. R. Giger stated, "I liked it particularly because I found it was in the vein of Lovecraft, one of my greatest sources of inspiration."
Lasting critical praise
Alien has continued to receive critical acclaim over the years, particularly for its realism and unique environment. It has a 97% approval rating at the online review aggregator Rotten Tomatoes based on 89 reviews, while Metacritic gives an 83% approval rating based on 22 reviews. Critical interest in the film was re-ignited in part by the theatrical release of the "Director's Cut" in 2003. Despite having criticized Alien in 1980, Roger Ebert included it in his "Great Movies" column in 2003, ranking it among "the most influential of modern action pictures" and praising its pacing, atmosphere, and settings:
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: The interception of a signal (is it a warning or an SOS?). The descent to the extraterrestrial surface. The bitching by Brett and Parker, who are concerned only about collecting their shares. The masterstroke of the surface murk through which the crew members move, their helmet lights hardly penetrating the soup. The shadowy outline of the alien ship. The sight of the alien pilot, frozen in his command chair. The enormity of the discovery inside the ship ("It's full of ... leathery eggs ...").
McIntee praises Alien as "possibly the definitive combination of horror thriller with science fiction trappings." He notes, however, that it is a horror film first and a science fiction film second, since science fiction normally explores issues of how humanity will develop under other circumstances. Alien, on the other hand, focuses on the plight of people being attacked by a monster: "It's set on a spaceship in the future, but it's about people trying not to get eaten by a drooling monstrous animal. Worse, it's about them trying not to get raped by said drooling monstrous animal." Along with Halloween and Friday the 13th (1980), he describes it as a prototype for the slasher film genre: "The reason it's such a good movie, and wowed both the critics, who normally frown on the genre, and the casual cinema-goer, is that it is a distillation of everything that scares us in the movies." He also describes how the film appeals to a variety of audiences: "Fans of Hitchcockian thrillers like it because it's moody and dark. Gorehounds like it for the chest-burster. Science fiction fans love the hard science fiction trappings and hardware. Men love the battle-for-survival element, and women love not being cast as the helpless victim."
"Almost every horror film since Alien has ripped it off in some way, but most of the imitations have focused on details — a slimy killing-machine monster that is both vaginal and penile; the dripping, cavernous interiors of the Nostromo; those immensely influential H. R. Giger 'biomechanical' designs — and missed what you might call the overall Zeitgeist of the film."—Salon.com critic Andrew O'Hehir
Salon.com critic Andrew O'Hehir notes that Alien "has a profoundly existentialist undertow that makes it feel like a film noir" and praises it over its "increasingly baroque" sequels as "a film about human loneliness amid the emptiness and amorality of creation. It's a cynical '70s-leftist vision of the future in which none of the problems plaguing 20th century Earth—class divisions, capitalist exploitation, the subjugation of humanity to technology—have been improved in the slightest by mankind's forays into outer space."
David Edelstein wrote, "Alien remains the key text in the 'body horror' subgenre that flowered (or, depending on your viewpoint, festered) in the seventies, and Giger’s designs covered all possible avenues of anxiety. Men traveled through vulva-like openings, got forcibly impregnated, and died giving birth to rampaging gooey vaginas dentate — how’s that for future shock? This was truly what David Cronenberg would call 'the new flesh,' a dissolution of the boundaries between man and machine, machine and alien, and man and alien, with a psychosexual invasiveness that has never, thank God, been equaled."
In 2002, Alien was deemed "culturally, historically or aesthetically significant" by the National Film Preservation Board of the United States, and was inducted into the National Film Registry of the Library of Congress for historical preservation alongside other films of 1979 including All That Jazz, Apocalypse Now, The Black Stallion, and Manhattan. In 2008 the American Film Institute ranked Alien as the seventh-best film in the science fiction genre as part of AFI's 10 Top 10, a CBS television special ranking the ten greatest movies in ten classic American film genres. The ranks were based on a poll of over 1,500 film artists, critics, and historians, with Alien ranking just above Terminator 2: Judgment Day (1991) and just below Ridley Scott's other science fiction film Blade Runner (1982). The same year, Empire magazine ranked it thirty-third on its list of the five hundred greatest movies of all time, based on a poll of 10,200 readers, critics, and members of the film industry.