There's an interesting approach to the story construction of The Human Centipede series the way each successive film exists in the world of the later films, one that continues in the far more comic third instalment.

The villain/protagonist of this film, Martin (Laurence Harvey) is inspired to action by his unhealthy obsession with The Human Centipede, which he watches on a constant loop in the office of the underground London parking garage where he works.

The conceit of the film is that Martin – in a very unselfconscious performance by Harvey as the diminutive, filthy, overweight and silent psychopath – is the creation of a lifetime of abuse. He's antisocial, uncommunicative and turns out to be every bit the Dr Crippen-style sicko we fear anyone like him might actually be.

From licking his wormy little lips and fingers at the most inappropriate stimulus to masturbating with sandpaper, writer/director Tom Six is up to his old tricks of taking every awful idea he has and turning it way up.

Martin keeps a scrapbook full of photos from the movie and his drawings inspired by it, and his sick and twisted ambition is to make a living human centipede out of 12 people, believing the tagline of the original that it's 100 percent medically accurate.

He goes from his dingy flat and abusive, unhinged Mum to work and when the opportunity strikes he surprises, incapacitates and kidnaps his victims. He's leased a broken-down, unkempt industrial workshop that's like something H R Giger and Fritz Lang would dream up together, which is where he deposits his victims until he has enough to carry out his ambition.

He simply leaves them there for days at a time, tied up and naked on the floor, occasionally hitting them over the head with a tyre iron to keep them quiet.

Six's intentions are right out there at the forefront of the film. With Martin's capture of a heavily pregnant woman – who makes the only escape of the group, ends up giving birth in the car she's stealing to get away and deals with the baby in the most horrific fashion – he's hoping simply to make you gasp with revulsion like he's Lars von Trier's teenage younger brother.

The other possible creative intent is less obvious. It seems like Six is beating his critics to the punch on their condemnation of the previous film - and trying to one-up them. The Human Centipede II is a meta-comment on the kind of damage such filth does to society when sickos see this kind of rubbish, the kind of person his critics and related wowsers always claim would love the first movie.

His whole mission statement seems to be to bait the firmament that's historically complained about everything from video nasties to pornography, and it might make him the most effective marketer working in film today.

There's also a cheeky subplot that both homages and subverts the series when Martin plots to have the leading lady from the original fly to London believing she's attending an audition for Quentin Tarantino. He collects her from the airport posing as her driver, takes her straight to the dank garage with the rest of his victims and sets about installing her at the head of his human centipede.

The original film was tamer than you've heard. Six did actually pull punches and cut away from the worst images and it was more the idea than the visuals that were so over the top – there was certainly no more blood, terror or violence than you see in the average horror or war movie.

The Human Centipede II is nastier, more like a traditional horror movie – possibly because there are more people suffering, but probably also because the high contrast black and white makes the proceedings all the more gloomy, as if Martin is some kind of angel of death stealing the colour out of people's lives.

In a way, it's actually more in the spirit Six seems to have wanted for the original when it comes to being classic horror. That's a roundabout way of saying it's 'better', but such a term depends completely on your point of view.