It's hard to think of any film that can be satisfactorily compared to The Human Centipede.
Some have lumped it in with the 'torture porn' of Saw and Hostel. That's a fair comment, but that will disappoint those who watch it expecting the full gore and special effects.
Most of what you see is implied. Even the psychological terror can only be perceived in our own heads, prompted by tearful expressions on the screen.
I've read rants about only sick individuals coming up with this concept; and only warped viewers watching it. There are the usual fears of a real life copy-cat attempting the surgery. Also the fact that Tom Six declared that Mengele was an inspiration for Heiter has given rise to accusations that this movie is disrespectful to Holocaust victims.
The Human Centipede doesn't make pleasant viewing, but it's difficult to align this with reality. As someone who wrote her dissertation on the Holocaust (and organized the Memorial Day, with its speakers including one of Mengele's actual victims), I saw no hint of that in there. Mengele and Heiter were both immoral and unethical doctors, not coincidentally sharing the same first name, and that's where the similarity ends.
Even the tag-line claim that the surgery is '100% medically accurate' is dubious. No doubt the grafting could be done, but it would certainly be followed by death through shock and dehydration. Or we can take our pick from choking/asphyxiation, malnutrition and so on.
Could the human centipede survive for years? No, it couldn't. A doctor has confirmed this (video), pointing out the likelihood that even the tissues would be rejected before the individuals died.
I don't accept that films should not be made because they are too 'gross'. I find it more disturbing that the movie has been banned in some countries, than anything depicted in the fictional scenes.
Censorship always gives me pause; and I've encountered some commentators poised to turn this movie into a cause célèbre.
Pushing the boundaries of what is shocking keeps not only the horror genre alive, but comedy too. This is why the two are often interchangeable. Some are convinced that The Human Centipede was meant to be a comedy horror, but I think that's just in the bad writing.
Then there are those who reject the film outright, because it's a great idea surrounded by a truly dismal narrative. And those who call it genius for the same.
The point is that in an age when conformity of opinion appears so popular, there is no collective reaction to the movie. Is it a good film or a bad film? It's hard to say. But it's causing a lot of debate and maybe therein lies the clue.
If only Tom Six had employed a great screen-writer to run with his idea, it might have been perfection within the horror genre.