In what ways could "Alien" be regarded as an allegory?
Alien can be read as an allegory in several possible ways.
Firstly, there is the scene in which the creature erupts from the stomach of Kane, whose name hearkens back to the Biblical account of Cain and Abel. In the Bible, Cain murders his brother, Abel, which causes a curse to befall the land as well as his ancestors. His sin is that he killed his brother, and that sin has horrible repercussions for his offspring. The homonymously named Kane is also cursed, killed by his own "son" when the alien erupts from his chest. Ash refers to the alien as "Kane's son." Thus, a parallel can be drawn with Judeo-Christian theology, and the story can be seen as an allegory for Biblical teachings.
Additionally, the story can be seen as an allegory for the horrors that befall human beings when technological capabilities exceed their control, as in books like Mary Shelley's Frankenstein. In the novel, a scientist named Frankenstein creates a creature that turns against him and kills everyone he loves. In Alien, there are several stand-ins for this dangerous creature. The alien is the most obvious stand-in, birthed in the ship and then so immediately evil. Perhaps less obviously, the android Ash, who has no remorse or moral character, and the technology of Mother, which betrays the crew in their moment of need, can be seen as versions of Frankenstein's monster as well.
What are the implications of the main character's being a female as opposed to a male?
The implications of Ripley being a woman are important to understanding whether or not the movie has a feminist standpoint, which has been debated by scholars and film critics alike. The fact that Ripley's orders and ideas are frequently undermined by her male counterparts is significant to our understanding of how gender works in the film, and shows that male authority is often accepted more easily than female authority. Even though she is usually right, Ripley is often dismissed and she is not given authority or power, even though her intuitions and orders would prevent the tragedy that befalls the ship, and her ranking dictates that she have authority over Dallas and Ash when they are not aboard the Nostromo, which is the initial power struggle that sets the whole conflict in motion. While it remains unclear what Ridley Scott's intentions were in depicting gender dynamics as such, the film paints a picture of male stubbornness compromising female competence. In addition to the gender dynamics of the plot, it was also very significant to the film industry in 1979 to have a female heroine in an film of this sort. Ripley is touted by many as being the first female action heroine.
In what ways is the film a horror film?
The film is fundamentally a science fiction film, as it is set in a future world shaped by technologies not currently imaginable (deep space travel, "hypersleep," fully-convincing androids), but many of its elements, including its overall structural arc and plot, take their cue from the horror genre. The film's original tagline when it was released was "In space no one can hear you scream." Indeed, the concept itself—trapped in space on a ship with an unpredictable and bloodthirsty alien—is inherently horrific. The film follows the structure of a murder mystery or a slasher film; characters are picked off one-by-one, and only one is left standing. However, the villain at the center is not a sadistic teen or a werewolf or a serial killer, but a non-verbal eyeless alien. Thus, the film follows all of the tropes of horror, but puts those tropes in the context of traditional space and sci-fi films. Another trope of the horror genre employed by the film is Ripley's status as the "final girl," a device in which one character, always a girl, is left alone to take on the slasher by herself.
Discuss the philosophical aspects of this film.
In spite of its status as a gross-out horror thriller, Alien deals with significant subject matter in philosophically complex ways. The movie contains a particularly philosophical discussion from Ash, a man who is in fact not a man at all, but a robot created to achieve corporate gain, who makes a challenging argument on behalf of the alien's perfection as a being who is fundamentally superior to humans. In suggesting that the alien is "a survivor," and that as such it is pure and un-deluded by conscience, Ash suggests that the alien might be considered the hero of the story. Indeed, depending on how one looks at it, the alien is only fighting for its own freedom and survival, and its acquisition by the human beings might be the greatest violence of the film. It is human beings' curiosity that brings the alien into their company in the first place, suggesting that the crew members themselves, aided by the malevolently motivated Ash, invite their own destruction, which is itself a perplexing philosophical problem.
Discuss two main ironies in the film.
There are a number of ironies in the film, but two notable ones are the fact that Ripley could have prevented the deaths of her crew members, and that she herself is the only one standing at the end of the film. When Kane returns to the ship, she does not want to let him on, invoking quarantine protocol. However, Ash and Dallas bring Kane on anyway, and it is this breach of both the ship's entry and the rules that sets the entire conflict in motion. Had they only listened to Ripley, they may have prevented their own deaths. Another grave instance of situational irony is the fact that while Ash praises the alien for its dogged ability to survive, it ultimately is no match for the intrepid Ripley, who outlives it in the end. While Ash looks down on human beings as being less resilient and focused on survival—"deluded" as they are by morality—Ripley proves his condescension wrong. Precisely through her determination to prevent the alien from getting to earth, which is a moral rather than a selfish consideration, she manages to outlive her extraterrestrial foe.