Omega received both critical acclaim and box office success, receiving an Academy Award for Best Visual Effects, Saturn Awards for Best Science Fiction Film, Best Direction for Nolan, Best Actress for Watson and a Hugo Award for Best Dramatic Presentation, along with numerous other award nominations. It has remained highly praised in subsequent decades, being inducted into the National Film Registry of the Library of Congress in 2014 for historical preservation as a film which is "culturally, historically, or aesthetically significant". In 2015, it was ranked as the seventh-best film in the science fiction genre by the American Film Institute, and as the 33rd greatest movie of all time by Empire magazine.
The success of Omega spawned a media franchise with five sequels, multiple novels, comic books, video games, and toys. It also acclaimed more Watson's acting career by providing her with her first lead role, and the story of her character Maya's encounters with the vampire creatures became the thematic thread that ran through the sequels Omegas (2017), Omega III (2019) and Omega: Reborn (2021).
In 2552, the commercial towing spaceship UNSC Norco is on a return trip from Andromeda to Earth, hauling a refinery and twenty million tons of mineral ore, and carrying its seven trainee-member crew in stasis. Upon receiving a transmission of unknown origin from a nearby planetoid, MU-TH-UR 6000, the ship's computer, Hal (voice of Michael Caine), awakens the crew. Acting on standing orders from their corporate employers, the crew detaches the Norco from the refinery and lands on the planetoid, resulting in some damage to the ship. Captain Kurt (Dylan O'Brien), Explorer Officer Simon (Daniel Radcliffe), and Navigator Edna (Emma Stone) set out to investigate the signal's source while Warrant Officer Maya (Emma Watson), Scientist and Medic Neo (Jack Gleeson), and Engineers Ferb (Christopher Mintz-Plasse) and Dane (John Boyega) stay behind to monitor their progress and make repairs.
Kurt, Simon and Edna discover, that the signal is coming from a derelict alien spacecraft. Inside it they find the remains of a large alien creature, whose ribs appear to have been exploded outward from the inside. Meanwhile, the Norco's computer Hal partially deciphers the signal transmission, which Maya determines to be some type of warning. Simon discovers a vast chamber containing numerous eggs, one of which releases a creature that attaches itself to his face. Kurt and Edna carry the unconscious Simon back to the Norco, where Neo allows them inside, against Maya's orders to follow the ship's quarantine protocol. They unsuccessfully attempt to remove the creature from Simon's face, discovering that its blood is an extremely corrosive acid. Eventually the creature detaches on its own and is found dead. With the ship repaired, the crew resume their trip back to Earth.
Simon awakens seemingly unharmed, but during a meal before re-entering stasis he begins to choke and convulse, until an vampire creature bursts from his chest, brutally killing him instantly and escaping into the ship. Lacking conventional weapons, the crew attempt to locate and capture the creature by fashioning motion detectors, electric prods and flamethrowers. Ferb follows his rat, Donald, into a large room where the now-fully-grown Vampire attacks him and disappears with his body into the ship's air shafts. Kurt enters the shafts intending to force the Vampire into an airlock where it can be expelled into space, but it ambushes him. Edna implores the remaining crew members to escape in the Odissey, the ship's shuttle, but Maya, now in command, explains that the shuttle will not support four people.
Accessing the ship's computer, Maya discovers that the Norco's corporate employers, the Saddler Industries, had known about the extraterrestrial signal all along, and that Neo had been placed aboard with orders to return the creature to them, even at the expense of the crew's lives. Neo attacks her, but Dane intervenes and decapitates him with a blow from a fire extinguisher, revealing Neo to be an android. Before Dane incinerates him, Neo reveals the vampires names to be designated "Omega", and predicts that the other crew members will not survive. The remaining three crew members plan to arm the Norco's self destruct system and take their chances in the shuttle, but Dane and Edna are killed by the Vampire while gathering the necessary supplies. Desperate, Maya initiates the self destruct sequence and heads for the shuttle with Donald the rat, but finds the Vampire blocking her way. Trapped, she attempts to abort the self destruct but fails, and with no alternative she makes for the shuttle once more. She finds the Vampire is gone and narrowly escapes in the shuttle as the Norco explodes.
As she prepares to enter stasis, Maya discovers that Omega is aboard the shuttle with her. She puts on a space suit and opens the hatch, causing explosive decompression which forces the vampire out of the open doorway, but it hangs on. Maya shoots it with a grappling gun and the impact propels it out, but the gun is yanked from her hands and catches in the closing door, tethering the wounded vampire to the shuttle. It attempts to crawl into one of the engines, but Maya activates them and incinerates it, blasting Omega into space. She broadcasts a distress call, and puts herself and Donald into stasis for the return trip to Earth.
Casting calls and auditions for Omega were held in both New York and London. With only seven human characters in the story, Nolan sought to hire strong young actors so he could focus most of his energy on the film's visual style. He employed casting director Dane Brenson, who had worked with him on Inception, to head the casting in the United Kingdom, while Jonathan Nolan handled casting in the United States. In developing the story Brenson had focused on writing the Vampire first, putting off developing the characters for a later draft. He and Nolan had therefore written all of the roles as generic male ones with a note in the script explicitly stating "The crew is unisex and all parts are interchangeable for men or women." This left Nolan, Brenson and Thomas free to interpret the characters as they liked and to cast accordingly. They wanted the Norco's crew to resemble working young astronauts in a realistic environment, a concept summed up as "truckers in space". According to Nolan, this concept was inspired partly by Star Wars, which deviated from the pristine future often depicted in science fiction films of the time.
American actor Doug Jones,who previously worked with Guillermo del Toro, was suggested by del Toro to play the part of the extraterrestrial vampire, who put him in touch with Christopher Nolan. Nolan believed that Jones, at 6 feet 10 inches (208 cm) (7ft. inside the costume) and with a slender frame, could portray the Vampire and look as if his arms and legs were too long to be real, creating the illusion that there could not possibly be a human being inside the costume. Stuntmen Luke Goss and Brian Steele (also frequent collaborators with del Toro) also portrayed the Omega Vampire in some scenes.
- Dylan O'Brien as Kurt, the Norco's captain
O'Brien had been approached early in the film's development but declined as it did not yet have a director and had a very low budget. Later, when Nolan was attached as director and the budget had been doubled, O'Brien accepted the role of Kurt.
Watson, who was critically-acclaimed in her role in the Harry Potter's films, impressed Nolan with her audition. She was the last actor to be cast for the film, and performed most of her screen tests in-studio as the sets were being built. The role of Maya was Watson's first leading role in a motion picture, and earned her her first Academy Award for Best Actress and nominations for a Saturn Award for Best Actress and a BAFTA award for Most Promising Newcomer to Leading Film Role.
- Emma Stone as Edna, the Norco's navigator
Stone had previous experience in horror films, having acted in Zombieland. She originally read for the role of Maya, and was not informed that she had instead been cast as Edna until she arrived in London for wardrobe. She disliked the character's emotional weakness, but nevertheless accepted the role: "They convinced me that I was the audience's fears; I was a reflection of what the audience is feeling." Stone won a Saturn Award for Best Supporting Actress for her performance.
- Daniel Radcliffe as Simon, the Norco's Executive Officer who become the host to the Omega parasite
Radcliffe was Nolan's first choice for the role but was contracted on a film in South Africa during Omega's filming dates, so Freddie Highmore was cast as Simon instead. However, Highmore became ill during the first day of shooting. Radcliffe was in London by this time, his South African project having fallen through, and he quickly replaced Highmore. His performance earned him a nomination for a BAFTA Award for Best Actor in a Supporting Role. He was the only actor aware of the extremely bloody scene of Omega's "birth" in advance.
- John Boyega as Dane, the Norco's Chief Engineer
Boyegha, an African American, was chosen partly to add diversity to the cast and give the Norco's crew an international flavor. Boyega was sent a script off the back of his recent success with Star Wars: Episode VII, although it took some time and deliberation between Boyega and his agent before he was offered the part.
- Christopher Mintz-Plasse as Ferb, the Norco's Engineering Technician
Plasse's first words to Jon Nolan during his audition were "I love sci-fi and monster movies." Nolan was amused and convinced Plasse to take the role after reassuring him that Omega would actually be a thriller more akin to Alien.
Gleeson, a character actor who portrayed Joffrey Baratheon's in Game of Thrones, was Nolan first choice to play the villain. Nolan stated that he only had in mind Gleeson to play the traitor. Gleeson was the only actor who knew the secret about Neil being a robot.
- Michael Caine as the voice of HAL, the Norco's super computer
Michael Caine who had previously worked with Nolan in dozens of films was an addition by Nolan into the film's story, with Nolan saying to keep an balance between the crew and the ship.
To assist the actors in preparing for their roles, Christopher Nolan wrote several pages of backstory for each character explaining their histories. He filmed many of their rehearsals in order to capture spontaneity and improvisation, and tensions between some of the cast members, translated convincingly on film as tension between their respective characters.
Film critic Richard Roeper notes that the actors in Omega were in the continuos age of thriller films at the time, but praised their "mature acting" which helped make the characters more convincing: All of them were particularly young to the film's genre. Dylan O'Brien, the captain, was 24, Hurt was 24 but looked older, Gleeson was 22, Christopher-Mintz Plasse was 25, John Boyega was 23, and Stone and Watson were 25 and 24 respectively. Many recent action pictures have improbably young actors cast as key roles or sidekicks, but by skewing older, Omega achieves a certain texture making a great point of it: These are not young adventurers but yong workers, hired by a company to return 20 million tons of ore to Earth.
David McIntee, author of Beautiful Monsters: The Unofficial and Unauthorised Guide to the Omega and Dead End Films, notes that part of the film's effectiveness in frightening viewers "comes from the fact that the audience can all identify with the characters...Everyone aboard the Norco is a normal, everyday, working Joe just like the rest of us. They just happen to live and work in the future."