Continuity: When Paul Kersey is first mugged for his wallet, they are all in an outdoor market area with Spanish architecture and smaller buildings. When we see Kersey chase after Jiver and corner him in an alley, they now appear to be in a downtown location with traditional high-rise buildings.
Continuity: When Bronson traces the final group of muggers and gets onto an LA-bus nearly an hour into the movie, the number on the bus is different when Charlie steps in as to when he leaves the bus.
Revealing mistakes: There are obvious spotlights in the background when Charles Wilson makes his escape.
Revealing mistakes: It is obviously fake blood in the scene where Kersey is bleeding and trying to hide it from his lover.
Errors made by characters (possibly deliberate errors by the filmmakers): The doctor supposed to be giving therapy to Charles Wilson is named Dr. Clark, yet Kersey writes the name Dr. Carter on the fake hospital ID.
Errors made by characters (possibly deliberate errors by the filmmakers): When Kersey goes to the hospital to kill Charles Wilson, he parks in a handicap space.
Errors made by characters (possibly deliberate errors by the filmmakers): When Kersey returns home after killing Charles Wilson, he parks in a fire lane, clearly denoted with a "no parking any time" sign.
Errors made by characters (possibly deliberate errors by the filmmakers): Paul's girlfriend (Geri) enters Paul's bedroom while Paul is asleep. Paul awakes and calls her "Jill".
Errors made by characters (possibly deliberate errors by the filmmakers): When Paul Kersey is at KABC radio, he is informed about the murder of the N.Y.C. cop at the park in L.A. He was actually informed that five people were murdered including the N.Y. cop although Charles Wilson got away, only Cutter, Jiver, the cop, and the gun dealer were the only ones that were actually murdered.
Errors made by characters (possibly deliberate errors by the filmmakers): After Paul Kersey kills Charles Wilson, the hospital attendant arrives in the room. When he finds that Wilson is dead, Kersey tells him that he attacked and killed Kersey's daughter. However, Jiver actually attacked Kersey's daughter and she was never killed - she jumped out of a window to her death.
Errors made by characters (possibly deliberate errors by the filmmakers): After Jiver attacks the housekeeper, Nirvana (Charles Wilson) orders Stomper to take the housekeeper into the bedroom but calls Stomper "Nirvana".
Revealing mistakes: When Paul fires the single shot at Nirvana in the hospital, Nirvana is flipping a table up and pushing it towards him. In spite of firing directly into it, no bullet hole appears in the white tabletop.