* ActingInTheDark:
** Tom Six kept the actual method of how the centipede would be formed secret from nearly everyone as long as possible.
** Akihiro Kitamura wrote his monologue for the scene where [[spoiler:Katsuro commits suicide]].
* ActorInspiredElement: Creator/DieterLaser contributed many ideas about Heiter's character, the most notable of which was him swimming naked in front of his victims; he felt that since Heiter viewed the 'centipede' as his pet, he wouldn't be ashamed to be naked around them. He also supplied the jacket that, according to him, was worn by real Nazi doctors.
* AuthorPhobia: The main villain is a surgeon, because Tom Six has a personal fear of hospitals and doctors. This is also why the scene of Dr Heiter explaining what he'll do is so drawn out - as he wanted to create his "own nightmare".
* AwesomeDearBoy: Akihiro Kitamura [[https://www.youtube.com/watch?v=3rPoml_ok74 said]] that he happily took the role of Katsuro upon being told that he'd spend half the movie with a beautiful woman attached to his ass.
* BannedInChina: ''Full Sequence'' suffers from this.
** In the UK, the film has been [[http://www.joblo.com/horror-movies/news/the-human-centipede-2-banned-in-the-uk-details-revealed- refused classification]] by the BBFC. The ban was eventually lifted, but only after several cuts were made.
** In Germany, as much as '''17''' minutes had to be cut, but even then, this wasn't enough to placate the authorities, ultimately banning the film outright.
** In Australia, the film initially passed uncut but ultimately had to be edited, albeit not to the extent of the UK cut, to pass.
** In New Zealand, the film is banned outright.
* CaliforniaDoubling: Set in Germany, filmed in the Netherlands.
* TheCastShowOff: Creator/DieterLaser is multilingual and speaks both German and English in the film.
* EnforcedMethodActing:
** Ashley C Williams and Ashlynn Yennie shared an apartment during filming to better develop chemistry as lifelong best friends.
** The film was shot in chronological order to allow the actors to develop their characters.
** Creator/DieterLaser remained in character and avoided the other actors to create a feeling of separation.
* HostilityOnTheSet: A fight broke out between Creator/DieterLaser and Akihiro Kitamura after the former accidentally kicked the latter.
* InspirationForTheWork: Tom Six claims that he got the idea for the film from discussions with a friend on how to punish child molesters. One of them came up with stapling the pedophile's mouth to the ass of a fat truck driver. As sort of a DevelopmentGag on the above, the first subject Heiter procures for his experiment is in fact a fat truck driver - once he has two more subjects, he finds the trucker is "not a match" and just kills him.
* OneTakeWonder: The scene of mouth defecation was done in one take.
* ReferencedBy:
** In the song Red Flags by Creator/{{Tom Cardy}}, the protagonist go on a date with a girl obsessed with the first movie and initially thinking that she's crazy;[[spoiler:she ended up planning to create a human centipede with their wedding to save money.]]
** South Park make the episode [[Recap/SouthParkS15E1HumancentiPad HumancentiPad]] where Kyle is put in he middle of a human centipede made by Steve Jobs.
* ThrowItIn:
** Akihiro Kitamura improvised his dialogue in the scene where Heiter explains his procedure.
** The heating wasn't working in the scene where Lindsay falls into the pool, so Ashley C Williams's shivering was real.
* WriteWhatYouKnow: Tom Six drew inspiration from his time as a director for ''Series/BigBrother'', where he observed the strange things people would do when they were alone and thought they weren't being watched.
----