* BTeamSequel: Creator/KennethBranagh turned down directing this film as he felt that the locked release date didn't give him enough pre-production time that he decided to work on ''Film/JackRyanShadowRecruit'' instead.
* BillingDisplacement:
** Despite being the main villain (and even being on the poster), Creator/ChristopherEccleston's name doesn't appear in most of the promotional material, including said poster.
** The end credits sequence includes individual credits with headshots of most of the cast, including Alice Krige (who only shows up in one scene) and Creator/ChrisODowd (who appears in two) -- but not Jonathan Howard, who played the much bigger and more plot-significant role of Ian.
* ContractualObligationProject: Creator/NataliePortman signed on under the understanding that Creator/PattyJenkins was going to direct. Jenkins ended up leaving the project a few months after she officially signed on for CreativeDifferences and Portman tried to leave with her. She would later back down once she realized that there was no way out of her two film contract to avoid litigation from Creator/{{Disney}}’s ArmyOfLawyers.
* CowboyBebopAtHisComputer: Hilariously, [[http://www.ign.com/articles/2013/11/07/chinese-movie-theater-uses-fan-made-thor-2-poster a theater in Shanghai mistakenly picked up a fan-edited version of the film's poster]], featuring Loki photoshopped into Jane's place in Thor's arms, and used it to promote the movie instead of the official poster.
* CreatorBacklash: Of all the Marvel movies, ''Dark World'' seems to have been the one that most of the cast and crew working on found to be a generally unpleasant time.
** Alan Taylor is [[http://uproxx.com/movies/terminator-genisys-alan-taylor/ not particularly fond]] of his experience on making the movie. He claimed that he was given a lot of freedom when he was filming only for ExecutiveMeddling to change everything in post-production. An interview he gave in 2021 revealed that Taylor actually suffered a CreatorBreakdown as the difficulties of getting this movie made as well as the failure of ''Film/TerminatorGenisys'' almost caused him to quit filmmaking altogether.
** Creator/IdrisElba apparently didn't have a good time making the movie, and claimed the shoot was tedious and exhausting.
** Creator/NataliePortman wasn't too happy with this project from the start, to the point where she reportedly attempted to quit in protest of the departure of initial director Patty Jenkins, and only stayed on because it was less trouble than potentially getting sued for breach of contract. In mid-2016, she said that she was very unlikely to ever reprise her role as Jane, though she later mended fences with Marvel Studios, resulting in her eventually returning for ''Film/ThorLoveAndThunder''.
** Creator/ChristopherEccleston, who admitted he only took the role in the first place [[MoneyDearBoy for the money]], said Marvel misled him by neglecting to mention that he'd be required to sit in a makeup chair for 6-to-8 hours a day to have his makeup and facial prosthetics applied. For extra chagrin, a lot of his character's scenes were cut, meaning such pains were for nothing. Ultimately, he [[http://www.radiotimes.com/news/tv/2018-03-12/christopher-eccleston-says-doctor-who-exit-almost-destroyed-his-career/ later]] described making the film as "Just a gun in your mouth." He did, however, enjoy working with Alan Taylor, Chris Hemsworth - with whom he shared skepticism on the film's bleak tone - and especially Anthony Hopkins.
** Creator/PattyJenkins revealed years later that she left the film due to finding the script abysmal, which she knew full well would be blamed on her if she stayed and permanently wreck her career.
** Creator/ChrisODowd found the experience of shooting the film so unmemorable that [[https://twitter.com/getfandom/status/1093162166784589824?lang=en he forgot he was even in the movie a few years later.]]
* CreatorCouple: Creator/ChrisHemsworth's wife Creator/ElsaPataky was Creator/NataliePortman's stand-in and played Jane in the post credit scene.
* DeletedScene: [[DeletedScene/MarvelCinematicUniverse See here]].
* DyeingForYourArt:
** Creator/ChrisHemsworth grew out his hair for over a year to have more authentic long hair rather than use a wig. (A particularly funny part of the HilariousOuttakes is his hair entering Hemsworth and Natalie Portman's mouth during a kiss.)
** Little to no [=CGI=] was used for Creator/AdewaleAkinnuoyeAgbaje's Kurse, so he had to wear massive prosthetics for the role.
* ExecutiveMeddling: Malekith had more of a backstory to tell but because of Tom Hiddleson's popularity, Loki received an expanded role in the plot, which resulted in this backstory being removed to save time.
* FakeBrit:
** Chris Hemsworth (Australian), Jaimie Alexander (US American) and Hopkins (Welsh) portray Asgardians with English accents.
** Zachary Levi (Fandral) is American.
* FirstAppearance: This film marks the first time an acknowledged Infinity Stone makes an appearance. The Tesseract and Loki's scepter would get a RetCon as containing Infinity Stones (Space and Mind, respectively), but they showed up before Phase 1 was truly locked in.
-->'''The Collector:''' One down. Five to go.
* FocusGroupEnding: This film was originally supposed to be Loki's last appearance, but the ending was changed due to negative reaction to his death at the test screenings. In the final version, Loki fakes his death and then casts a spell on Odin to take his place as the king. Thor and Jane's amiable break-up was also excised.
* InMemoriam: The film was dedicated to Don Payne, who was co-writer on both this movie and its predecessor.
* LoopingLines: The scene where Thor and Loki are arguing on the skiff while flying through Svartalfheim had to be completely dubbed, due to the dialogue being inaudible because of the large fans on set.
* MoneyDearBoy: Creator/ChristopherEccleston openly admits he did this one for two reasons: the chance to work with Alan Taylor, and the big fat paycheck.
* OnSetInjury: Creator/JaimieAlexander suffered severe injuries when she slipped off a metal staircase during a rainy morning on the set. The fall caused her to slip a disc in her thoracic spine and chip 11 of her vertebrae, as well as dislocate her left shoulder and tear a rhomboid on her right side. The injuries took her out of filming for a month.
* TheOtherDarrin:
** Creator/ZacharyLevi replaces Creator/JoshuaDallas as Fandral due to Dallas' commitment to ''Series/OnceUponATime''. Ironically, Levi was supposed to play Fandral in the first ''Thor'' but had to back out because he was committed to Series/{{Chuck}} at the time.
** In the French dub, Creator/AlexandreGillet replaced Maël Davan-Soulas as Steve Rogers/Captain America. Davan-Soulas voiced him in ''Film/CaptainAmericaTheFirstAvenger'' and ''Film/{{The Avengers|2012}}''.
** For the French dub again, regarding Odin, Creator/AnthonyHopkins' usual dubbing voice Creator/BernardDheran passed away in January 2013. He was replaced by Jean-Pierre Moulin.
* PromotedFanboy: While it was ultimately cut, a scene featuring Malekith and Odin was filmed. Anthony Hopkins had been one of Christopher Eccleston's inspirations for becoming an actor.
* RecursiveAdaptation: Malekith was an obscure and forgotten villain from Thor comics. The film briefly raised the interest in him again, so he was used again as a regular villain. And, although the MCU Malekith turned out to be rejected by the audiences and never showed up again, the returned Malekith in comics proved to be quite a success.
* ThrowItIn: The gag of Thor hanging his hammer on a coat hook in Jane's apartment was an improvised bit by Creator/ChrisHemsworth who obviously thought that a warrior prince/god like Thor would be mindful of the proper etiquette of checking one's weapons when you enter another's home.
* UncreditedRole:
** Creator/JossWhedon did an uncredited rewrite.
** Creator/ChrisEvans is uncredited for his cameo as Captain America when Loki impersonates him.
** Creator/BenicioDelToro and Creator/OpheliaLovibond are uncredited for their appearance in TheStinger.
* WhatCouldHaveBeen:
** Creator/MadsMikkelsen was the original choice for the role of Malekith before Creator/ChristopherEccleston was cast, but turned it down due to scheduling commitments to ''Series/{{Hannibal}}''. Mikkelsen would eventually go on to portray Kaecilius in ''Film/{{Doctor Strange|2016}}''.
** Creator/PattyJenkins was originally chosen to direct the movie before [[Film/TerminatorGenisys Alan Taylor]] was hired, but departed the project due to CreativeDifferences with Creator/MarvelStudios. Jenkins wanted to change the story up a bit, but the people at Creator/{{Disney}} didn't want to run the risk of rewrites delaying filming and missing its release date as it was the only big live-action tentpole of the very important holiday quarter. Jenkins' version of the script having a tone similar to ''Theatre/RomeoAndJuliet'' and heavy focus on Thor and Jane Foster's relationship. Several years later, Jenkins would also note that when she first read the script, she hated it, and knew that if she signed on that the bad script would be tied to her name and potentially sink her career.
---> '''Jenkins:''' It was painful and sad because I really loved those guys and I loved the idea of us making a Thor together, but it’s one of those things. You have to make sure that the movie you want to make is fully the right movie for that studio too. It was heartbreaking, but I also knew that it was good… I knew that it was good because I didn’t think I could make a great film out of their script.
** Music/CarterBurwell was originally signed to score the movie but, at the last minute, it ended up in the hands of Music/BrianTyler ([[Film/IronMan3 not the first time he'd done a movie set within the Marvel Cinematic Universe]]), who had to put together the score in a matter of ''weeks.''
** [[ComicBook/ValkyrieMarvelComics Valkyrie]] of ''ComicBook/TheDefenders'' was set to appear at one point, and concept art of her costume was even drawn up. Valkyrie would later debut in ''Film/ThorRagnarok'' portrayed by Creator/TessaThompson.
** Creator/KevinFeige [[https://www.cbr.com/hela-thor-the-dark-world-main-villain/ revealed in an interview]] that ComicBook/{{Hela}} was originally planned to be the BigBad, but it didn't happen 'for various reasons' and Malekith ended taking her place. Of course, Hela ended up being the villain for ''Film/ThorRagnarok'', played by Creator/CateBlanchett.
** Like the previous film, Balder was planned to appear with concept art of him in the frontlines against the Dark Elf forces.
** Alan Taylor wanted to have a CreatorCameo as the archer who [[spoiler: lights Frigga's boat at the funeral]], but he was turned down for insurance reasons.
** An early ending of the final battle against Malekith had Thor concentrating lightning from all nine realms to destroy him and the Aether, since his method of using only one lightning like on Svartalfheim was ineffective. However, the filmmakers wanted all characters to contribute to Makekith's demise, so they added Jane, Selvig and Darcy using the gravity spikes to help Thor.
** In the original script and during the principal photography, [[https://screenrant.com/loki-thor-dark-world-death/ Loki's death was meant to be for real.]] However, the test audiences refused to buy it, citing LikeYouWouldReallyDoIt and causing a rewrite to the ending, showing Loki's ultimate survival.
** A lot of material was scrapped in post-production to take advantage of Loki's popularity. This included a good deal of Malekith's scenes (which provided him with a FreudianExcuse) and the entire character supporting character of Tyr, portrayed by Clive Russell (from ''Series/GameOfThrones''), being removed from the film (although he still shows up on the background).
** According to Making of the MCU book, Creator/BenedictCumberbatch was a frontrunner of Malekith before he was eventually cast as Doctor Strange.
** Thor and Jane had a scene at the end of the film where they amiably break up, concluding that their ways of life were not compatible and the universe only drew them together to help safeguard it. This ended up being deleted, and Jane instead stayed together with Thor until breaking up with him off-screen by the time of ''Film/ThorRagnarok''.
* WordOfGod: [[spoiler:Odin's]] fate [[http://www.comicbookmovie.com/fansites/movienewsandreviews/news/?a=89868 had been given different answers by some of the crew.]] Kevin Feige didn't outright answer the question but said that there are plans for him, Alan Taylor thought he's dead but wanted to know how he would end up in the sequel, and Creator/AnthonyHopkins didn't have an idea and believed that he's dead. ''Film/ThorRagnarok'' finally answered the question, Odin was not dead, Loki ensorcelled him and banished him to Earth. [[spoiler:He does die during the events of ''Ragnarok'' though.]]
* WordOfSaintPaul: Some of Creator/TomHiddleston's comments in interviews suggest that he has been quietly shipping Loki/Jane since the first movie, believing they have a connection that has not been explored in-story.
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