Revealing mistake: After Forrester picks up the school bus sign, there's a shot of a Martian machine blasting at a bridge. Looking closely, the light poles can be seen through the machine, showing the model was matted over the background.
Revealing mistake: As the spaceship heads back into space, it leaves the same way that it crashed - they reversed the film. (01:18:30)
Revealing mistake: In the beginning where Vincent Price is brawling with his business partner, his partner throws a pipe or bar at him. Price ducks and the bar hits something that the camera was connected to, because the scene jerks.