Alongside Romano Scavolini’s Nightmare/Nightmares in a Damaged Brain (1981), William Lustig’s Maniac is the scuzziest of the early 1980s slashers, a censor-baiting gorefest that trailed controversy wherever it went. It’s an uncomfortable watch – intentionally and necessarily so – but it can also be a dreary one. Unusually for an 80s slasher – and this is also a trait it shares with Nightmare – we know who the killer is from the very start. He’s the very unwell Frank Zito (Joe Spinell) who, like Norman Bates before him, has some heavy-duty mummy issues. Abused as a child by his prostitute mother (Nelia Bacmeister) he’s grown up to be a woman-hating serial killer who scalps his victims and attaches their hair to the mannequins he keeps around his squalid New York apartment. We see him murdering a prostitute on a hotel, shooting a man (the film’s effects make-up designer Tom Savini) at point-blank range and murdering his date, and ranting at his mannequins.

A small chance of redemption comes in the shape of fashion photographer Anna D’Antoni (the first American film for Caroline Munro) who seems inexplicably eager to befriend him. He confides in her about his mother but finds it impossible to give up his murderous ways, putting Anna in danger. His madness finally consumes him and, in the film’s hard-to-fathom climax, is attacked by the mannequins that come to life and attack him – or he commits suicide, its hard to tell really.

Lustig came from a porn background and Maniac has that same, grainy, shot-on-16mm feel to it. He used the profits of adult film Hot Honey (1978), which he directed under the pseudonym Billy Bagg, to help fund Maniac and pays homage to the film with a “hot honeys” graffito in the toilet of a subway where Zito claims another victim. His direction is largely perfunctory, just getting the job done with little finesse or style. Where he scores is in creating an atmosphere of unremitting grimness – Zito’s horrid apartment is sharply contrasted with the more opulent uptown apartment Where Anna lives and its vision of New York as a grubby den of sex and violence takes Martin Scorsese’s Taxi Driver (1976) to its bleak extremes.

Elsewhere, the murders are lingered over, the scalpings are suitably grisly, there’s an unbearably tense chase through a deserted subway station and in the killing of Tom Savini’s character, one of the most (in)famous exploding heads outside of David Cronenberg’s Scanners (1981), a scene inspired in no small part by the killings committed by the Zodiac killer. But the plot is a meandering mess, its attempts at psychological insight are laughable and it stretches credulity too far to expect us to believe that Anna would even give someone like Zito a second look.

Balancing all that are several plusses, not least of which are some excellent performances. Zito is a horribly convincing character thanks to the ever-sweaty Spinell who is genuinely unsettling as the increasingly unhinged killer. By all accounts Spinell was a charming man (“I loved Joe,” Munro told The Flashback Files website. “He was very eccentric, but very caring at the same time. He had his demons, but everybody who worked with him loved him”) but so convincing is he in the role of Zito that you would have run a mile if you’d ever met him. He plays Zito not as the quasi-supernatural killer that would gradually become the norm in the slasher film, culminating in dream demon Robert Englund in A Nightmare on Elm Street (1984), but a slobby, embittered, sexually frustrated and deeply damaged nobody railing against women for the abuse inflicted on him by his sadistic mother (his body is covered with scars).

It’s a deeply unsettling turn and Spinell leads an interesting cast that also included a couple of adult film stars that Lustig brought with him from his former life – Sharon Mitchell turns up as a nurse, Abigail Clayton as Rita, one of Zito’s victims. Early trade adverts announcing the film listed Jason Miller, Susan Tyrell and Daria Nicolodi as Spinell’s co-stars. Again, talking to The Flashback Files, Munro remembered that “Joe and I were attending a Fangoria convention in New York and he told me their actress hadn’t turned up to do Maniac, because she was still working” – which would have been Nicolodi who was still attached to Dario Argento’s Inferno (1980) at the time. What became of Miller and Tyrell isn’t clear – perhaps they baulked when they saw the script and realised exactly what they were getting into.

Also in the credit column is a superb electronic score by Jay Chattaway, the first from the man who would later go on to score several entries in the Star Trek franchise: The Next Generation (1987-1994), Deep Space Nine (1993-1999), Voyager (1995-2001) and Enterprise (2001-2005). At a time when too many horror film scores of the time were the work of John Carpenter wannabees holding down notes on synthesizers they didn’t know enough about to program effectively, it’s a nuanced and at times rather chilling piece of work.

Maniac is a deeply conflicting film. It certainly delivers the goods in terms of violence and gore (look out for the disembodied head of Mrs Vorhees from Friday the 13th (1980) doing double duty at the end and there’s a head-ripping at the climax that anticipates Savini’s similar gag in Day of the Dead (1985)) but the misogyny is uncomfortable and the plot too meandering – Munro claimed that much footage was removed before release, including material that would have explained exactly why Anna was so intrigued by Zito. What’s left is a muddled film, never more so than in the odd finale. Is any of that actually happening or just a product of Zito’s madness? And where do those cops come from who speed to Zito’s apartment, discover his body and then just wander off without doing anything about it?

But Maniac undeniably found its audience and rapidly became a cult favourite. Spinell teamed up with director Buddy Giovinazzo to make a short promotional film for a proposed sequel, Maniac 2: Mr Robbie in 1986, which would also have served as a remake of Larry G. Brown’s The Psychopath (1973). The project was abandoned when Spinell died in 1989, though Lustig continued to develop a remake independently, stating that he’d like to see Tom Sizemore take over the role. It eventually appeared in a very unusual film in which Elijah Wood took over the role but was rarely seen, the film being shot from the point of view of his murderous character. It proved to be a very different film from the original.