Revealing mistake: Near the end, when Eliot enters Frank's office with his rifle, he accidentally shoots into the ceiling. He shoots it at a slight angle, but the rubble falls right on top of his head instead.
Revealing mistake: The palm trees next to the building Arthur came out were not real trees. One is flush against the front wall of the building and another is in a nearby corner. The palm tree in front looked completely flat - like a large piece of cardboard or maybe painted on the wall. Palm trees should be at least 30' away from a structure as well as outdoor pipes, buried lines, etc. They grow a big central root below the trunk and MANY thin roots running horizontal close to the surface - some may be exposed. (00:05:51)
Revealing mistake: Clearly not Susan Blakely when she goes topless. Her hair suddenly becomes curlier, that's a body double.