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)
Continuity mistake: Big Joe gets out of his jeep, salutes Captain Maitland, and converses about the upcoming time off for the men. Behind Big Joe is one of his half tracks and he is on Maitland's right. The scene cuts and Maitland's "liberated" yacht is behind Big Joe and he is directly in front of Maitland. (00:25:00)
Continuity mistake: Iris splashes Coffin Ed with the glass as he speak into the phone receiver. She barely gets him and in the same shot as he turns towards the camera to grab her, his jacket and shirt have barely any wet spots. Throughout the scene the stains change in number and size for no reason (even assuming some might have dripped from the cheek to the jacket). (00:17:45 - 00:18:55)
Visible crew/equipment: When the police investigator is speaking with the man standing outside the store window and asks him if he would buy every tie in the store, in every close-up shot of the investigator, the reflection of the cameraman kneeling on the ground can be seen in his sunglasses. (01:08:25)
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.
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.
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)