Directed by: Fred F. Sears
Starring: Hugh Marlowe, Donald Curtis, Joan Taylor, Morris Ankrum
Revealing mistake: When Carol, Dr. Marvin and the others enter the alien spaceship it's obvious by the sound that that they are walking on plywood made to look like metal. (00:37:10)
Revealing mistake: As the alien's speak to Carol, Dr. Marvin and the others inside their spaceship, they use the exact same footage again of them looking at the video screen as they leave earth even though one minute of movie time has elapsed. (00:39:25)
Visible crew/equipment: Dr. Marvin decides to try out his new improved magnetic interference unit on a real alien spaceship that shows up outside the Belmont lab. As the truck with the device on it pulls up you can see the reflection of the crew in its door. (00:51:50)
Carol Marvin: My father! What have you done to him?
Alien: You're addressing General Hanley's mind, not General Hanley.
Trivia: Paul Frees is the apparent "spokesperson" for the aliens. His voice is heard throughout the movie. He's also the voice visitors hear in "The Haunted Mansion" rides at the Disney parks.