Continuity mistake: When the Apes are trying to break into the mutant's church, Mendez looks towards the Alpha/Omega bomb, and is wearing a cream-colored jumpsuit with a purple sash. When the Apes do break in, his sash has disappeared. (01:25:50)
Visible crew/equipment: When Mike and Susan prepare to start putting pieces of snow in the kettle, in the shot where Susan hands Mike the kettle, and he begins taking the lid off, the camera crew can be seen reflected on the kettle. (01:16:00)
Continuity mistake: During Prince Rupert's first appearance, he greets his uncle King Charles I by doffing his hat and putting it back on. In the close-up shot he is holding his hat in place but in the wide shot his hand is on his side.
Continuity mistake: When Reverend Deke unmasks the guy in blackface, he lowers the hand he had on his shoulder. Return to the close-up: the hand is again present. (01:23:40)
Continuity mistake: After speaking with the plumber at the Homicide Decision, the investigator and a colleague begin walking down a hallway and the colleague puts his hand on the investigator's arm. When this happens, the investigator has a small cup of espresso raised up to his face. When the camera changes angles, the small cup of espresso is suddenly lowered away from his face. (01:23:15)
Deliberate mistake: When the family first entry Three Chimneys they have a single lamp as a light source. Entering from the door at the rear of the shot, everything in front of them should be in darkness to the viewer, but it's lit. Things in the background are lit even though there would be no line of sight to the light source. This is because lighting was added on set to allow the viewer to see things better, even though it ruined the realism.
Factual error: During the scene where Clint Eastwood is trying to convince Don Rickles to join in the heist, there is a box of Almond Joy candy bars behind Don's head. They weren't introduced until 1946. (00:28:50)