Dennis Storhøi was cast as Sander but was fired by van Heijningen after repeatedly showing up on set too drunk to work, according to an interview van Heijningen gave to the fan site "Outpost 31". He was replaced by Ulrich Thomsen.
The producers convinced Universal Studios to allow them to create a prequel to John Carpenter's The Thing (1982) instead of a remake, as they felt Carpenter's film was already perfect, so making a remake would be like "painting a mustache on the Mona Lisa". However, the prequel still has the title of the original film, because they couldn't think of a subtitle (for example, "The Thing: Begins") that sounded good.
In order to not try to compete with Kurt Russell's portrayal of the 1982 film's protagonist, R.J. MacReady, the character of Kate Lloyd was designed to have traits in common with the character Ellen Ripley from the Alien (1979) film series.
The first draft of the screenplay was written by Ronald D. Moore in 2009, though Universal then opted to have the screenplay rewritten by Eric Heisserer. However, in 2013 Moore became a co-producer and writer on the series Helix (2014) which features an extremely similar premise (a team of scientists at a remote Arctic research base combating a lethal alien virus-like organism that horrifically mutates humans and could wipe out humanity if it spread).
The creature effects were done primarily with cable-operated animatronic robots on the director's insistence, since it would improve the performances of the cast if they saw what they had to react to. Computer-generated images were used to add elements to the animatronics (such as tentacles), or in some cases, to replace the entire animatronic if it didn't behave convincingly.
The song Kate is listening to on her headphones is "Who Can It Be Now?", a song by Australian band Men at Work from their 1981 debut album, "Business as Usual". The lyrics tell of a paranoid man who hears knocking at his house door and wishes to be left in solitude. This foreshadows the paranoia of the scientists later in the film.
The songs the crew are singing are "Sámiid Ædnan", the Norwegian entry in the 1980 Eurovision Song Contest, originally sung by Sverre Kjelsberg and Mattis Hætta. And the other one is called "Jeg gikk en tur på stien" (translated: I walked along the forest path), a well known children's song about someone walking in the woods, and meeting a cuckoo. The origin of this song is unknown.
When Carter and Jameson return to the camp, they stumble past a funny signpost full of city names and their distances. One of the cities that can be clearly read is Amsterdam, which is where director Matthijs van Heijningen Jr. is from.
When the team first enters the cave to look at the ship, there is a snow/ice formation which looks remarkably like the head of the xenomorph from the alien series, weather it is on purpose or a happy accident is unknown, however coincedentally the effects team on this film, Alec Gillis and Tom Woodruff Jr. have been working on the alien franchise since 1986 Aliens to 2007 AVP: Requiem
The trivia items below may give away important plot points.
The red axe that Joel Edgerton's character uses and eventually sticks into the wall can be seen still stuck in the wall when the Americans visit the Norwegian camp in the original John Carpenter version.
This film may have purposely solved a long-standing mystery in the 1982 film. This film reveals that The Thing cannot replicate abiotic things such as fillings, earrings, clothes, etc. and at a pivotal moment near the end, Kate realizes that Carter's earring is missing as well as the hole for the piercing revealing him to be a Thing. At the end of the 1982 film, the character Childs still has his earring in his right ear. It can be seen just before he takes a drink from the bottle of J&B.
The burnt Thing with two merged heads that MacReady and gang find at the Norwegian site (in The Thing (1982)) is the same organism created when the Wolner-Thing lowers itself onto Finch and assimilates the latter by joining faces.
The signal at the beginning of movie when the Norwegians find the space ship, sounds like the S.O.S. signal from Danny Boyle's movie Sunshine (2007), when the Icarus 2 crew snapped the signal from the Icarus 1. This is because both signals are based on actual sounds received from space, the origin of which are still unknown.
Originally, a different beginning and ending to the movie had been partially filmed, which would have shed more light on the Thing's backstory. The prologue would have shown how the alien pilot purposely crashed the ship on Earth, and then committed suicide. Later, an alien that was in the process of becoming a Thing would exit the ship in order to kill itself by freezing. At the end, as Kate (Mary Elizabeth Winstead) enters the ship, she finds the interior littered with dead aliens, either dismembered, burnt or in a state of transformation. In the central area, she sees the last alien pilot hanging, with its throat slit. According to director Matthijs van Heijningen Jr., the implication was that the alien race piloting the ship was collecting other alien specimens. One such specimen was a Thing, which had broken out of its confinement pod, leading to a massacre among the aliens and other specimens similar to what happened at the Norwegian base. The Sander-Thing, having taken the form of the pilot, suddenly attacks Kate, but she holds it back by threatening to use a grenade and blow both of them up. Then Carter (Joel Edgerton) enters and uses his flamethrower on the Pilot-Thing, to fool Kate into believing that he is human. After early screenings, the studio didn't think the Pilot-Thing was scary enough, and the climax was becoming too complicated, with Kate trying to stop the Sander-Thing as well as discovering the Thing's backstory at the same time. So the backstory was omitted, a new computer-generated Sander-Thing was inserted at the last minute, and a Tetris-like animation was added to the scene where Kate enters the central area to hide the dead alien pilot.
The character Lars (Jørgen Langhelle) is supposed to be the same Norwegian as the one who is shot to death in the beginning of The Thing (1982) after trying to kill the Dog-Thing (he is the one wearing the goggles with the horizontal slits). In a deleted scene from The Thing (1982), the Americans find dog tags on his body, identifying him as 'Jans Bolan'; however, since this information did not make it to the screen, the makers of The Thing (2011) were free to call him Lars instead.
The character Colin (Jonathan Walker) can be seen with his throat and wrist sliced at the end, which is the exact way the Americans found him in The Thing (1982). A scene was filmed showing how Colin has locked himself in the room behind the door where Carter (Joel Edgerton) puts his axe in. He then hears movements from the arm-Things closing in on him. With nowhere left to go, Colin takes his razor, slices his wrist, then sits down and slices his own throat. The scene was deleted for pacing reasons but can be viewed as a bonus feature on the BluRay edition.