Critical response
The film has a rating of 27% at Rotten Tomatoes based on 81 reviews, with a weighted average of 3.28/10. The site's consensus reads: "The Human Centipede II (Full Sequence) attempts to weave in social commentary but as the movie wears on, it loses its ability to repulse and shock and ends up obnoxious and annoying." At Metacritic, it rates 17 out of 100, indicating "overwhelming dislike", based on 22 reviews.
Giving it a score of 7 out of 10, Bloody Disgusting writer Brad Miska said the film was a "brilliant response to critics of his first film. It makes a strong statement that it's just a movie and that people take his work way too seriously, while also implementing a unique concept". Miska added that he "found it an intensely engaging and absolutely hilarious meta experience that gets its point across with flying colors", but was critical of the script's lack of depth. Entertainment Weekly writer Owen Gleiberman gave the film a B+ rating, stating that viewers "may feel gripped by the horror of what you're seeing and the terror of what's coming". Gleiberman noted how "The scatological climax would have the Marquis de Sade gagging into his popcorn." Writing in the New York Post, V. A. Musetto gave the film 3 out of 4 and said Full Sequence "is sick, disgusting and vile. (but) It's also demonically funny, stylish and ingenious."
Jen Yamato, writing for Movieline, criticized the film's excessive gore and the way director Tom Six seemed to dislike his own audience, specifying "It's not really a film one can or should 'enjoy', which is what Six seems to be telling his own audience, the fans who giggled through The Human Centipede and demanded more! Gorier! More extreme! Well, those people will get what they asked for." Eric Kohn, writing for indieWire, criticized the excessive grotesqueness of the film as well as Six's vanity. He stated, "Well, what if it turns someone's own body against them—is that a measure of success? To some degree, yes; it's designed to turn the tables on its own gore-hungry fans by depicting a fictionalized version of one of their own so revolting they think twice about their twisted tendencies. But it's so indulgently perverse, and so viscerally disturbing to watch—not to mention a painfully vain exercise in self-worship—that the lesson is incredibly hard-won. Take a word of warning, if you're on the fence; you don't have to see The Human Centipede II to know you don't want to see it."
Some reviewers found the extreme nature of the film boring. Robert Koehler, writing for Variety, found the gore so excessive that he termed it a form of lazy filmmaking. "More boring than stomach-churning, the film nevertheless contains scattered scenes and sequences so far beyond the tolerance of the squeamish that it can't be overstated; one, detailing the violent birth and death of a baby, is here simply to shock the most jaded of the jaded".
Reviewer Robert Saucedo of InsidePulse.com was more generous toward the film, but found its execution lacking. He wrote, "The film ... has a hint of intelligence hiding behind its beady little eyes. Smeared with blood and poo as it may be, this intelligence exposes a film that has something to say. The problem, unfortunately, is that director Tom Six is like a child—attempting to make a profound statement but unable to get it out eloquently or even in anything not resembling a whimper or a groan most of the time ... Who would have guessed? Human Centipede II is a treatise about horror fandom as delivered by a giggling, poop-infatuated toddler."
Mark Olsen, film critic for the Los Angeles Times, expressed concern over the film's conclusion as well as its basic premise. The conclusion (which he admits is open to interpretation; did Lomax commit these crimes or not?) leaves the audience either believing that the film is a "cop-out repudiation of everything that has come prior" or that even more graphic torture is coming in the third film. Regardless, Olsen concluded that writer-director Six has left himself with no good option for the third film.
Roger Ebert, of the Chicago Sun-Times, who did not assign a star rating to the original, gave this film zero stars on review, calling it "reprehensible, dismaying, ugly, artless and an affront to any notion, however remote, of human decency". He would later name it the worst movie of 2011.
In the UK, the reception of the film was just as hostile. Scott Weinberg and Catherine Shoard in The Guardian and Mark Kermode in The Observer praised the BBFC for heavily censoring the film, their only regret being that the BBFC could not make The Human Centipede 2 into a "better" film.
As with the first film, the medical accuracy was criticized, with Philip Coakley, then a medical doctor training to specialize in gastroenterology and the respiratory system, noting during an interview with Vice magazine that the procedure could lead to complications including vomiting, choking, pneumonia, asphyxia, hypothermia, dehydration, malnutrition, diarrhea, and diseases and infections such as Escherichia coli.
