he film’s most incredible set piece is the multi-block revolt scene. Here, Mayor Hatcher of Gary [in Indiana] was instrumental: He allowed [director Ivan] Dixon to burn down an entire block, provided a helicopter for aerial shots, and allowed the police force to be used as extras. The latter is imperative because the Gary police department was mostly Black, creating a conflicting and complex vision of the limits of integration.[…]
There even was an instance of locals unwittingly becoming involved in the film. “A lot of those people that ended up joining the action weren’t actors. They weren’t working for us at all. They just came to beat up the police,” recalls ['Shorty' actor Pemon] Rami. “There’s a scene where there’s a woman fighting with her purse. She wasn’t with us. She just happened to be walking down the street and got involved with it, and they pushed her in, and she fought with the police.”
— Robert Daniels (RogerEbert.com)
[Director Ivan] Dixon, a successful television actor known for his wholesome role on Hogan’s Heroes, paid for the rights for Sam Greenlee’s novel The Spook Who Sat by the Door out-of-pocket. He sold the film to United Artists using a few clips of inoffensive action footage that looked to them like typical “Blaxploitation” fare. When executives saw the final cut, they were stunned. They had been duped into financing a movie about deceiving unsuspecting white folks, whose foolishness, it is implied, will eventually lead to their downfall. To boot, their contract with Dixon forbade them from cutting anything without his permission, and they were obliged to release it in at least 36 theaters.
— Elizabeth Horkley (Los Angeles Review of Books)