Josh Brolin and Peter Dinklage in Sibling Crime Caper.

The increasing dominance of streaming content over theatrical releases continues with “Brothers,” a Legendary Entertainment production that distributor Amazon MGM Studios released to a handful of theaters for a week without critical screenings ahead of its Oct. 17 debut on Prime. This strategy may prove to be a godsend for a moderately amusing feature film that lacks the heft to compete at the box office as awards season begins, leaving the film to find a less engaged audience in the streaming-verse.

Josh Brolin and Peter Dinklage play mismatched siblings with strong jaws (enhanced in Dinklage’s case by a mustache) in Max Barbakow’s second feature, in which he trades the subtler comic shades of Palm Springs for wry humor, to disappointingly weakening effect.

A brief setup introduces career criminal Jady Munger (Dinklage), who manages to have a significant portion of his sentence for burglary and assault thrown out after making a secret deal with corrupt judge Farful (M. Emmet Walsh).

Under the watchful eye of Farful’s corrections officer son James (Brendan Fraser), Jady agrees to help recover and hand over a stash of stolen emeralds worth millions that his mother Cath Munger (Glenn Close) had stolen years earlier left behind when she went on the run to avoid arrest. To accomplish his plan, Jady tries to recruit his twin brother Moke (Brolin), who wants to get started right away after teaming up with Jady in several robberies that also nearly landed him in prison.

After initially getting used to Dinklage and Brolin playing twins, you tend to settle for the familiar twists and turns of an entertaining heist comedy. But these expectations are quickly dashed by a ridiculously complicated family drama.

When Jady shows up uninvited at the baby shower for Moke’s pregnant wife Abby (Taylour Paige), Moke’s carefully compartmentalized life is in danger of falling apart – unless he can appease Jady by agreeing to use his safe-cracker skills to get to the emeralds. As the brothers embark on a road trip to pull off the job, with Officer Farful close behind, Moke has little idea that a world of hurt awaits Jady in his misguided attempt to build familial bonds.

Jady’s intermittent voice-over narration attempts to piece together decades of missed opportunities and hard feelings between the brothers, while Dinklage’s slanted facial expressions and cajoling tone help weaponize Jady’s campaign of deliberate emotional manipulation.

However, any attempt at reconciliation fails when Moke finds out that Jady has been in contact with Cath for some time without telling him. Her sudden appearance after 30 years sends him into an emotional freefall before his mother and brother can catch up with him to focus on the logistics of the heist, which turns out to be far more unorthodox than anyone expected.

While their performances have never before hinted at a family resemblance, “Brothers” will now inevitably establish a connection between Brolin and Dinklage, who find the delicate sibling dynamic between the estranged brothers fertile ground for their less-appreciated comedic talents. Close proves inspired in casting the role of the conniving and unrepentant Cath, who shows little sign of maternal concern for her sons as she searches for the emeralds.

While the premise is reminiscent of zany brotherhood comedies like Adam McKay’s Step Brothers or Ivan Reitman’s Twins, Brothers lacks the quirkiness of the filmmakers’ previous work. It forgoes the winning humor that Barbakow memorably showcased in his Groundhog Day riff on Palm Springs or the wackiness of screenwriter Macon Blair’s The Toxic Avenger.

However, they provide tasteful characterization and fast-paced dialogue for the supporting cast and their stars, giving Fraser a cheerfully gonzo role as the angry Farful and sending Walsh off with a handful of choice lines in one of the actor’s seasoned final roles. Even Marisa Tomei’s cameo comes across as Jady’s prison correspondence, long-distance love and orangutan owner Samuel, who develops a perverse affinity for Moke in one of the film’s far too few laugh-out-loud scenes.

“Brothers” is dynamically directed by Quyen Tran and energetically scored by Rupert Gregson-Williams (backed by a selection of 70s pop hits). But for a film that aspires to vintage comedy, it packs far too much cast firepower into a slim plot and even sketchier character development. Whether a streaming audience will even notice the miscalibration is probably irrelevant, as long as they remember the unlikely brothers.