John Saxon and Daria Nicolodi co-star as Neal's agent and assistant respectively, while Giuliano Gemma and Carola Stagnaro appear as detectives investigating the murders.

The film has been described as exploring themes of dualism and sexual aberration, and has strong metafictional elements; some commentators consider Tenebrae to be a direct reaction by Argento to criticism of his previous work, most especially his depictions of murders of women.

Employing director of photography Luciano Tovoli, Argento also intended that the film simulate the stark, realistic lighting featured in television police shows at the time; production designer Giuseppe Bassan created supporting environments that were cold and austere, with sharp angles and modernistic spaces.

The film's theatrical distribution in the United States was delayed until 1984 when it was released in a heavily censored version under the title Unsane, which received a mostly negative critical reception.

"[8] These narrative and visual strategies had been introduced years before Argento made his first thriller, 1970's The Bird with the Crystal Plumage—most critics point to Mario Bava's The Girl Who Knew Too Much (1963) as the original giallo.

[9][10] By the time Argento made Tenebrae, he had become the acknowledged master of the genre, to the point where he felt confident enough to be openly self-referential to his own past, referencing the "reckless driving humor" from The Cat o' Nine Tails (1971) and the hero from The Bird with the Crystal Plumage.

[5] Warren and Alan Jones cite a scene where a character is killed in a public square as evoking the work of Alfred Hitchcock;[5][8] Thomas Rostock agrees that the editing of the sequence is in a Hitchcockian vein, while the lighting is more influenced by Michelangelo Antonioni.

[13] Kim Newman and Alan Jones suggest that the mysteries of Arthur Conan Doyle, Rex Stout, and Agatha Christie were all obvious influences on Tenebrae, and there are many references to these authors throughout the film.

[22] According to Argento expert Thomas Rostock, Tenebrae is filled with rhyming imagery that relates to the film's exploration of "the dual nature of [the] two active murderers" using doubles, inversions, reflections and "re-reflections".

[23] The doubling or mirroring of incidents and objects includes telephone booths, aircraft, homeless men, otherwise-meaningless public brawls in the background, car accidents, typewriters (literally side-by-side), keys, handkerchief, hands caught in doors and the characters themselves.

Berti's killings with a razor are clinical, with "lingering sexualized aggressiveness", whereas Neal's (with an axe) are crimes of passion committed for personal reasons or out of necessity; they are swift and to the point.

[16] Kevin Lyons observes, "The plot revolves around the audacious and quite unexpected transference of guilt from the maniacal killer (about whom we learn very little, itself unusual for Argento) to the eminently likeable hero, surely the film's boldest stroke.

Most obviously is the blind Franco Arno (Karl Malden) in The Cat o' Nine Tails, who must use his heightened aural sense in combination with visual clues supplied to him by his niece to solve a mystery.

Germani reveals that he is a big fan of the novels of Agatha Christie, Mickey Spillane, Rex Stout, and Ed McBain, but admits that he has never been able to guess the identity of the killer in any of the books.

[43] In an interview that appeared in Cinefantastique, Argento noted that the film was intended as near-science fiction, taking place "about five or more years in the future ... Tenebrae occurs in a world inhabited by fewer people with the result that the remainder are wealthier and less crowded.

[34] Despite Argento's claim, Maitland McDonagh observed that this vaguely science-fictional concept "isn't apparent at all" and that no critics at the time noted the underlying futuristic theme in their reviews of the theatrical release of the film.

I dreamed an imaginary city in which the most amazing things happen", she notes that the film's "fictive space couldn't be less 'real'", with its "vast unpopulated boulevards, piazzas that look like nothing more than suburban American malls, hard-edged Bauhaus apartment buildings, anonymous clubs, and parking garages.

"[49] The EUR district of Rome, where much of Tenebrae was filmed, was built in preparation for the 1942 World's Fair and intended by then-Prime Minister of Italy Benito Mussolini to be a celebration of twenty years of fascism.

[35] Nicolodi later claimed that although filming began well enough, Argento became angry when she and Franciosa bonded over playwright Tennessee Williams and their experience in theatre, leading the director to make sure their shared scenes "were an ordeal to endure".

Some of the homes – specifically those of the lesbian couple and the first killer – are "cold, austere, brutalist" slabs of granite,[31] and many of the interior shots feature plain white backgrounds, with characters' wearing pale-coloured clothes against them – better, Newman felt, to contrast the blood once the violence started.

[61] According to Gracey, the camera performs "aerial gymnastics", scaling the victims' house in "one seamless take, navigating walls, roofs, and peering in through windows, in a set piece that effortlessly exposes the penetrability of a seemingly secure home".

[70] The Italian rock band Goblin had provided the scores for two of Argento's previous films, Deep Red (1975) and Suspiria (1977),[71] but the director had employed English composer Keith Emerson for his foray outside of the giallo subgenre, 1980's Inferno.

Speculating in 2011, Thomas Rostock said that the higher-than-usual murder count for an Argento film was partially responsible,[32] while James Gracey believed it was perhaps "the highly sexualized presentation of its violent content".

"[52] Richard Dyer, writing for the Directory of World Cinema: Italy, describes the film as a "tease", one which is "perhaps the apotheosis of one of the core pleasures of detective fiction: being outwitted, wrong-footed, led up the garden path".

Club noted "... Argento makes some points about the intersection of art, reality, and personality, but the director's stunning trademark setpieces, presented here in a fully restored version, provide the real reason to watch.

"[91] Almar Haflidason, in a review for BBC Online, opined, "Sadistically beautiful and viciously exciting, welcome to true terror with Dario Argento's shockingly relentless Tenebrae.

"[79] Tim Lucas in Video Watchdog said, "Though it is in some ways as artificial and deliberate as a De Palma thriller, Tenebrae contains more likeable characters, believable relationships, and more emphasis on the erotic than can be found in any other Argento film.

We've got all the usual suspects, including a writer for a main character, lots of killer-cam point of view, some crazily over the top kills, and approximately seventy-two twists before all is revealed ... For fans of Argento's earlier giallo, this is a must-see.

"[96] In 2004, Tim Lucas re-evaluated the film and found that some of his earlier enthusiasm had dimmed considerably, noting that, "Tenebre is beginning to suffer from the cheap 16 mm-like softness of Luciano Tovoli's cinematography, its sometimes over-storyboarded violence (the first two murders in particular look stilted), the many bewildering lapses in logic ... and the overdone performances of many of its female actors".

[100] The final death scene in Tenebrae – where Neal is accidentally impaled by a sculpture – is directly referenced in Kenneth Branagh's Hitchcockian murder mystery Dead Again (1991).