Factual error: In the scene near the end of the film where Victor Buono is sitting in his chamber addressing his two captives, he opens a can labeled egg foo young with a can opener. He pours the liquid contents into a bowl. Egg foo young is an omelet and could not have passed through the small holes made with a can opener.

Revealing: At the end of the car chase when the two cars collide, the cliff shown to the right is a painting added to the scene to suggest a sharp drop off.

Continuity: When Gail tries to flee the wagon during the storm, the back of the car looks brand new; this despite being repeatedly rear-ended during the car chase.

Continuity: When Matt and Gail first pull over in the station wagon to spend the night, the car is parked at an angle between the trees. Later when it starts to rain, the car is parked straight.