What happens in Detour is rendered entirely through Roberts’ eyes, the action of the flashback consistently interrupted by creepy close-ups of him giving his version of the events. Like many a noir narrator, his reliability is constantly questioned by the film. He’s undercut by both his suspicious behavior in the death of Haskell (if he was really so innocent, why did he take Haskell’s money?) and his constant self-pity and blaming of "fate, or some other force" for what happens. And his attraction to the darkness and nihilism of Vera — why would he pick her (or anyone!) up after his own experience hitchchiking? — undermines his cries of victimhood.

Detour cost anywhere from $20,000 to $60,000, depending on which account you believe. It was shot in either four or six days, a typical schedule for many of Ulmer’s low-budget films. But it bears his distinctive stamp throughout. For the famous penultimate scene of Vera’s "accidental" murder, the camera seems to crawl inside Roberts’ head as he surveys the room where this happened, with the lens alternately focusing and defocusing on various objects. Even a simple scene like Sue singing is rendered with poverty-row panache with a low dutch angle of Sue backed up by three musicians seen only in shadow. Forced perspectives and expressionist motifs appear throughout, reinforcing the script’s vision of an unpredictable, ultimately terrifying world.

Actor Tom Neal’s career, like Ulmer’s, was restricted mostly to B films, but unlike Ulmer, Neal wound up in similar straits to Roberts. In an eerie life-imitates-art episode, he went to prison in 1965 for six years for killing his third wife. (Like Roberts, he claimed the killing was accidental.) Neal’s knockabout charm, his air of wounded virility, and his skill at rendering screenwriter Goldsmith’s stylized, rapid-fire dialogue make him one of noir’s most memorable beleaguered males, even if he does appear duplicitous or delusional in the end. Ulmer has spoken fondly of Al Roberts ("I was always in love with … the main character, a boy who plays piano in Greenwich Village and really wants to be a decent pianist," he told Bogdanovich), and no wonder. Roberts is easily read as a double for Ulmer himself — both men artists living a marginalized existence in straitened circumstances (Ulmer in B films, Roberts as a classical pianist in a dive). The great Ann Savage only appears in the second half of the film, but as Vera she dominates every scene, controlling Roberts and mesmerizing the viewer with her commanding stare and hard, sharp words. Savage also manages to give this harpy a human side when she makes it clear that she’s dying of tuberculosis. Savage appeared only sporadically in film in the 1940s and early ‘50s, but her reputation is secure on the basis of the unforgettable Vera.