When Eugene gets the car stuck in the sand on the side of the road, Raymond is pointing a gun at the guy who kidnapped Valerie. The gun changes from a Colt to a Baretta several times between shots.
Stuck in the sand scene, with each camera change the Beretta has the hammer down and the Colt has the hammer back.
After Eugene backs the Jeep halfway off the edge of the cliff, Raymond ends up falling out the back of the Jeep, knocking the tail gate open. Raymond is hanging upside down by his foot which is caught in a strap of some kind. A minute later, we see a shot from Eugene's point of view and see Raymond's hands gripping the top of the tail gate which is in back in the upright (closed) position.
Eugene's eggs change from cut up to just cooked and back to cut up during his breakfast conversation with Raymond.
When Dr. Monosoff sets up the broken chair at the conference table, he leaves no room to sit at the table without moving the chair (which would have obviously revealed the broken leg). When Eugene sits down, the chairs have been moved back allowing ample space to sit without moving the chair.
After Eugene shoots at the snake between Raymonds legs the snake is obviously being dragged away by its neck. No snake moves like that naturally.
Eugene's eggs change from cut up to just cooked and back to cut up during his breakfast conversation with Raymond.
When Eugene is in the plane in the backseat you can obviously tell that there is a door next to him yet when he gets out of the plane the door is much farther up.
When the chair is being broken to prove Eugene Proctor's bad luck, a person is visible under the table in one shot (wearing something blue).
Near the end of the movie, while Eugene and Valerie are walking together in the hospital, Valerie states what a beautiful hospital it is, and says that she's been to hospitals all over the world. However, she still has amnesia during this time period, and would not remember that.