Louis Gossett Jr. said in a TV interview that he had talked while gargling saliva as a kid as one of those kid things. He told the director that he thought that it would add a good touch to his character.
The whole film was originally shot in Vestmannaeyjar in Iceland, but when the first director and the producers disagreed on something (budget probably), the whole project was shut down. Wolfgang Petersen took over the direction and reshot the whole film.
Shot in the Bavaria Film Studios, Munich Germany; the outside sets are shot in Lanzarote one of the islands of Canary islands in Spain (all the volcanic/lava landscapes and the green lake)actually you still can visit those landscapes at the Lanzarote's "montaņas del fuego" national park. A few of the sets are still part of the studio tour.
Author Barry Longyear reported at a convention that the studio insisted on adding a subplot involving a mine, the studio thinking the audience would not realize that the "Mine" in the title was a possessive rather than an object.
During the opening battle sequence, the computer screen inside the Drac ship is actually displaying the structure of a protein.
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 was re-shot completely after the production suffered creative differences and cause to film to be delayed for almost a year and caused it to go over budget.
Among the original scenes that were shot from the "scrapped" version of the film was a longer finale where Davidge returns Zamus to his home planet and is introduced to Gerry's parent before the lengthy ceremony with the Drac high counsel takes place.
The pond where Davidge and Sheegan meet for the first time is the same artificial pond custom-built for the model submarine scenes of Boot, Das (1981), also directed by Wolfgang Petersen, as well as one or two scenes from Unendliche Geschichte, Die (1984), also a Petersen film.
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 has been 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.