From its earliest days, cinema has attempted to show viewers things that aren’t really there. Often, though, movies that withhold visual information are more powerful than those that reveal it all. And as Brothers of the Head and The Night Listener demonstrate, even films that don’t display everything can still show too much.

Directors Keith Fulton and Louis Pepe know that leaving some gaps in the narrative can boost a film’s sense of wonderment. That’s why, in Brothers of the Head, they use a now-familiar tactic to defy traditional fiction’s omniscience: They pitch their story, the tale of two literally symbiotic ’70s rockers, as a historical documentary that can only reveal what a previous set of filmmakers managed to capture on celluloid. Stylistically, this gambit largely works, in part because Fulton and Pepe know the genre from the inside: They’ve made several nonfiction movies, notably Lost in La Mancha, the 2002 account of Terry Gilliam’s failed attempt to film Don Quixote. Yet the picture’s successful aspects aren’t all a matter of form. They also include a compelling cast and something that most fictional pop-music flicks can’t muster: a persuasive score.

Adapted from a 1977 Brian Aldiss novella, Brothers of the Head is the tale of two sensual young men who are a lot closer than, say, the gangster and the rocker who swap lives in Nicolas Roeg and Donald Cammell’s epochal 1970 freakout, Performance. Tom and Barry Howe (Harry and Luke Treadaway) are conjoined twins, sharing internal organs and linked by a flap of skin. They should have been separated as infants, says a surgeon, but instead their father—mistrustful of doctors—exiled them to a remote cottage on a section of the Norfolk coast that just happens to be called “the Head.” At 18, their environment dramatically changes, when Dad contracts his boys to Zak Bedderwick (Howard Attfield), a vaudeville veteran turned manager who grasps the freak-show pedigree of fop pop and glam rock. He locks the Howes in a stately manor, where a group of unempathetic rock-’n’-roll tutors trains them as the frontmen of a combo dubbed the Bang Bang.

Tom, the stronger and nicer one, learns how to play guitar and writes pleasant ditties like “My Friend,” a tribute to his new paramour, journalist Laura Ashworth (Tania Emery). Barry, the charismatically weaker and meaner one, responds with proto-punk blasts like “My Friend (You C***).” An introductory number, “Two Way Romeo,” speeds the band to Britpop-style overnight fame, and two filmmakers arrive: American documentarian Eddie Pasqua (Tom Bower) and hysterical British romantic Ken Russell (playing himself). Their unfinished movies, supposedly, provide the raw footage for Fulton and Pepe’s retrospective film portrait.

The title of Aldiss’ book also refers to a third head that the brothers share; in the movie, this unsettling detail has been downgraded to an internal growth that doesn’t spoil the Howes’ pouty appeal. Fulton and Pepe present the twins’ conjoinment as more an emotional issue than a physical one, and scenes that purport to show the brothers’ corporeal link merely undermine the illusion that the actors are actually conjoined. (The fleshy connection doesn’t, for example, hamper Tom’s guitar playing.) If the mechanics of the Siamese-twin relationship always seem a little dubious, the plot is briskly propelled by its understanding of Britpop frenzy, as well as by Clive Langer’s songs. A member of Deaf School during the period simulated by Brothers of the Head, Langer is best-known for co-producing the likes of Madness, Elvis Costello, and Morrissey. The tunes he’s written (or occasionally co-written) for the Howe brothers are a shade too extreme for 1975 but are otherwise as exemplary as the Treadaway brothers’ rock-star bearing.

Yet if the attitude, music, and period details all click, that’s still not enough. Brothers of the Head doesn’t recall the eyeliner-flaunting variety of ’70s British rock just in sound and feel, but also in theme. Identity is slippery, image is powerful, fame is corrosive, and those who trifle too much with any of these forces will be destroyed—just as in such ’70s ego-smashing trips as Performance and The Rise and Fall of Ziggy Stardust and the Spiders From Mars. While Fulton and Pepe pose as historical filmmakers, they show no evidence of benefiting from three decades of hindsight. Rather than question glam rock’s adolescent self-analysis, they simply second it, yielding a film that’s less analysis than sham artifact.

In making The Night Listener, director and co-scripter Patrick Stettner would have been well-advised not to overly visualize the story. This is, after all, an adaptation of a book about a radio host’s purely telephonic relationship with an ardent listener. Visual options would seem limited to close-ups of mouths, ears, microphones, headsets, and telephones, perhaps supplemented by the sort of swoop-down-the-telecom-line shots Krzysztof Kieslowski employed in Red. Alas, Stettner decided to “open up” the narrative, thus rendering an intriguingly elusive tale into something that’s as predictable as a teen horror flick.

Based on Armistead Maupin’s semifictionalized tale, The Night Listener is a brief anecdote—expanded to 82 minutes only with the help of copious asides—from the life of a Maupin-like radio talker. Gabriel Noone (Robin Williams) doles out morsels of autobiography in rambling, lyrical raps, but his gift for gab has faltered since his younger lover, Jess (Bobby Cannavale), announced he’s moving out of Gabe’s New York town house. Hoping to divert the radio host’s attention, Gabe’s friend Ashe (Joe Morton) gives him a copy of an unpublished memoir. It’s the harrowing saga of a 14-year-old who was sexually abused by his parents, leaving him emotionally and physically devastated. Now battling AIDS, Pete Logand (Rory Culkin) is a big fan of Gabe’s show—and apparently a precociously gifted writer.

Soon Pete and Gabe are talking regularly, and Gabe wants to meet the boy. But Pete’s guardian Donna (Toni Collette) has abundant reasons why that can’t happen, arousing Gabe’s suspicions. When Jess suggests that Pete and Donna have the same voice, Gabe initially denies it. Yet soon he’s discussing the possibility that Pete is a fictitious character both with Ashe, who rejects it, and with his accountant Anna (Sandra Oh), who’s more skeptical of the boy’s persona. Frustrated by Donna’s series of proffered but then withdrawn invitations, Gabe travels to the wintry Wisconsin town where Pete and his protector supposedly live and tries to enlist the help of various uncooperative locals. Ultimately, Gabe breaks into Pete and Donna’s home, in a sequence that exemplifies what’s wrong with the movie: Stettner doesn’t trust Maupin’s ambiguous premise, so he embroiders it with the usual old-dark-house ploys, including deep shadows, eerie sounds, oblique camera angles, and shock cuts. The director might as well have installed a Jason or Freddy in the basement, waiting for Gabe to blunder down the stairs.

As the well-meaning radio host who’s finally hailed for his “great-big heart,” Williams suppresses his manic side, a maneuver that used to be impressive but now is a well-established alternative to his Mork-isms. The film belongs to the protean Collette, an actor playing a woman who is a very accomplished actor. One of the most vivid in Collette’s gallery of grotesques—a group that does not include her role in this week’s Little Miss Sunshine, a movie that’s practically a vacation for her dark side—Donna is the story’s mystery personified. When she’s on-screen, which by definition can’t be much of the time, the film is creepily alive. The problem is that most of what Stettner does to underscore Collette’s uncanny presence is so formulaic that it diminishes rather than amplifies the mood. The Night Listener may begin as a tantalizing psychological riddle, but it ends as the sort of haunted-house show Zak Bedderwick would understand.CP