Author Barry Longyear reported at a convention that the studio insisted on adding a subplot involving a mine, thinking the audience would not realize that the "Mine" in the title was a possessive (as in "My Enemy") rather than an object.
According to Louis Gossett, Jr., the Drac language was created from scratch. Much of it was Russian, pronounced in reverse.
The outside scenes (all the volcanic/lava landscapes and the green lake) were shot in Lanzarote (one of the Canary Islands off the coast of Morocco), at the Montañas del Fuego National Park. The rest was filmed at the Bavaria Film Studios, Munich, West Germany. A few of the sets are still part of their studio tour.
It took four hours to apply the make-up to Louis Gossett, Jr., to transform him into Jeriba.
In the scene where Davidge (Dennis Quaid) and Jeri (Louis Gossett, Jr.) argue about their respective philosophers and Jeri calls Mickey Mouse a "big dope", Dennis Quaid (Davidge) walks away from Jeri with a noticeable smirk, making a snorting noise consistent with trying to stifle laughter. This was actually the only take wherein Quaid didn't burst out laughing after the Mickey Mouse line, and his reaction was kept in order to make it clear that the scene is intended to be comedic and the bantering, while hostile, is meant to be friendly between the two.
After firing original director Richard Loncraine, newly appointed 20th Century Fox production head and Producer, Lawrence Gordon, green-lit the film again with Dennis Quaid and Louis Gossett, Jr., but this time, hiring Wolfgang Petersen as director. After taking over the project, Petersen decided not to use any of the footage that was already shot by Loncraine, and decided to start from scratch by relocating the entire production and building new sets in his native West Germany (the film was mostly shot at Bavaria Studios in Munich) and also redesigned Gossett's alien costume and make-up to look more like Barry Longyear's character as it is described in his book.
During the opening battle sequence, the computer screen inside the Drac ship is actually displaying the structure of a protein.
Louis Gossett, Jr. said in a television interview that he had talked while gargling saliva as a kid as one of those kid things. He told Director Wolfgang Petersen that he thought that it would add a good touch to his character. Gossett performed the odd vocalizations all by himself (no mouth prosthetics or post-production effects), and often does "the Drac voice" at convention appearances.
The pond where Davidge and Sheegan meet for the first time is the same artificial pond custom-built for the model submarine scenes of Das Boot (1981), also directed by Wolfgang Petersen, as well as one or two scenes from The NeverEnding Story (1984), also a Petersen film.
After being in a state of management flux, 20th Century Fox's new studio head Barry Diller and new Production Executive, Lawrence Gordon, green-lit Commando (1985), Big Trouble in Little China (1986), and the soon-to-be-hit sequels, The Jewel of the Nile (1985) and Aliens (1986). They continued with the production of this film, because they had Dennis Quaid and Louis Gossett, Jr. under costly contracts, for which the studio would've had to pay even after aborting the film.
Among the original scenes from the "scrapped" version of the film was a longer finale, where Davidge returns Zammis to his home planet and is introduced to Jeriba's parent, before the lengthy ceremony with the Holy Council takes place.
Original Director Richard Loncraine shot a lot of costly footage, around seventeen million dollars (mostly to Dennis Quaid and Louis Gossett, Jr., and the massive sets constructed for the production) before 20th Century Fox fired him.
To make a corridor look longer than it actually was, the crew created an optical illusion by putting a mirror in a 45° angle at the end of it. At the Bavaria Filmstudios, where the movie was filmed, you can still take a guided tour around the set. The effect with the mirror was so good, that one day a tour guide ran into the glass and broke it.
The rubber-like Drac ration balls were made from green Jell-O.
The film takes place from 2092-2095. When Davidge is rescued from Fyrine IV and brought to sickbay, his record shows he was declared Missing In Action (MIA) and presumed dead on July 11, 2092, and was found on Fyrine IV on September 6, 2095.
Terry Gilliam was offered the chance to direct, but turned it down, preferring instead to develop his own project, which would eventually become Brazil (1985).
The film's original budget was only seventeen million dollars at the start of the production when Richard Loncraine was the director and production was set in Iceland. When he was fired from the project and Wolfgang Petersen took over the film and started over, the film's final budget, including Loncraine's scrapped footage, ballooned to over forty million dollars.
The whole film was originally to be shot in Vestmannaeyjar, Iceland, but Richard Loncraine and the producers ran into "creative differences", and the project was shut down. Wolfgang Petersen took over and re-shot the entire film, with the production moving to Munich.
The empty soft drink can that Davidge finds in the film is Pepsi. In the novel of the film by Barry B. Longyear and David Gerrold, the empty soft drink can is Coca-Cola instead.
Author Barry Longyear said that the Drac's name, Jeriba Shigan, was meant to be a tribute to James Shigeta, who he would have liked to have seen as the Drac.
The majority of the film (Wolfgang Petersen's version) and post-production took place in West Germany, which also included the recording of Maurice Jarre's original score, which was recorded in Munich.
Some sets were re-used to shoot the music video of "TV Makes the Superstar" by Modern Talking.
Although the film is rated PG-13 in America, and PG in Australia and New Zealand. The film was given the 15 rating in England, due to the film's violence and gore such as a man being shot through the neck with a arrow. A man falling into a drill and killed, and a man finding his bloody severed ear, and a man shot in the back and falling into molten steel, which is strong for a PG rated film.
Film debut of Carolyn McCormick.
David Lynch was one of the directors considered.
Some scenes featuring Peter Jurasik were shot, but none were used.
The song Jerry sings in the film is "The Midnight Special" by Creedence Clearwater Revival.
Tom Baker was the voiceover in the trailer on a 1986 rental VHS tape in the UK.
Louis Gossett, Jr and Dennis Quaid also starred together in Jaws 3 (1983)
The film was released on DVD in New Zealand in July 2016.
Dennis Quaid played a similar role in Innerspace (1987). In this film, he's a space fighter pilot, and in Innerspace (1987) he played a down on his luck cocky Air Force pilot.
After this film Dennis Quaid would not return to outer space for 24 years, in 2009's Pandorum.
Davidge raising Zammis after Jerry dies foreshadowed Dennis Quaid's later film Savior (1998) in which Quaid's character in that film becomes the adopted father of a Yugoslavian baby girl, after her mother is killed.