"The Sisters Brothers," directed by Jacques Audiard, is generally well-received, praised for its unique blend of dark comedy and western elements. Starring Joaquin Phoenix and John C. Reilly as the titular brothers, the film explores themes of brotherhood, morality, and the impact of violence. Critics commend its strong performances, particularly from the leads, and its striking cinematography. While some viewers may find its pacing slow, many appreciate its unconventional approach to the western genre. Overall, it offers a thought-provoking and entertaining experience.

"The Sisters Brothers" is not based on a true story but is adapted from the novel of the same name by Patrick deWitt. The film, directed by Jacques Audiard, follows the fictional journey of two brothers, Eli and Charlie Sisters, who are hired assassins during the California Gold Rush. While the characters and events are imaginative, they reflect the historical context of the era rather than real-life individuals or events. The film combines dark humor and Western themes to explore brotherhood and morality.

In "The Sisters Brothers," the chemical referred to is a substance called "formula" or "the formula." It is a secret, highly valuable chemical compound that has the ability to locate gold in rivers. The character Hermann Kermit Warm, a prospector, creates this formula, which drives much of the plot as the Sisters brothers, Eli and Charlie, are tasked with tracking him down and retrieving it. The formula symbolizes the greed and ambition that underpin the gold rush era in which the film is set.

"The Sisters Brothers" was filmed in various locations across Europe and North America. Key filming locations included Spain, specifically in the regions of Andalusia and Almeria, which provided the film's Western landscapes. Additional scenes were shot in Romania and Canada, contributing to the film's authentic 1850s setting. The combination of these diverse locations helped create the film's unique visual aesthetic, showcasing the rugged environments of the Old West.