The film stars Arielle Holmes, Buddy Duress, Ron Braunstein, Eleonore Hendricks, Caleb Landry Jones and Yuri Pleskun.

After her release, Harley meets up with her friend, Mike, a low-level drug dealer, and another man she met earlier named Skully.

The site's critical consensus reads, "Grueling and rewarding in equal measure, Heaven Knows What hits hard -- and serves as a powerful calling card for its captivating star, Arielle Holmes.

[9] Kenji Fujishima of Slant Magazine described the film as "one of the most harrowing cinematic depictions of drug addiction in recent memory, reliant less on formal gimmickry than on close observation of behavior.

"[10] Jordan Hoffman of The Guardian gave it 5 stars out of 5 and praised Arielle Holmes' performance, saying: "While her accent is reminiscent of Linda Manz, her energy recalls Gena Rowlands in the best of Cassavetes' films.

[13] David Rooney of The Hollywood Reporter noted that "[among] the film's most impressive qualities is the Safdie brothers' boldly textural use of music — predominantly Isao Tomita's electronica versions of Debussy, but also a little Tangerine Dream and James Dashow as well as some hardstyle and black metal.

"[14] Nicolas Rapold of The New York Times commented that "[the] director of photography, Sean Price Williams, skillfully orchestrates lingering close-ups and up-the-street long shots, which are beautifully interwoven in the editing by Ronald Bronstein and Benny Safdie.