Factual error: The cemetery is full of bare branches of medium to small 'plants'. Since this is southern California, they should have leaves.
Continuity mistake: As he interviews Col. Edwards, the phone wires hanging off the side of General Roberts' desk move between shots without anyone touching a phone. (00:41:00)
Continuity mistake: In scenes at the general's office, a large wall map of the U.S. is in the background. In some of the closeups you can see that it's a Santa Fe railroad map - and in others the words "Santa Fe" on the logo are taped over. (00:42:05 - 00:45:30)
Revealing mistake: When the people in the military are firing the rockets at the UFOs, you can see the rockets launching from platform are coming from the outside of the platform. (00:19:00)
Visible crew/equipment: Inside the alien spacecraft, a compassionate Tanna says to Eros, "Do we have to kill them?" The shadow of the boom mike can be seen moving on the left of the screen above their heads. (01:02:20)
Continuity mistake: As they look into Tor Johnson's empty tomb, one of the police officers says it looks like (the dirt) has fallen into the grave. In the next shot as he goes into the hole there is no dirt in it. (00:40:00)
Visible crew/equipment: Someone's hand from behind touches the shower curtain in the cockpit of the plane as the pilot says, "You better radio in for landing instructions, Danny". (00:04:15)
Revealing mistake: In the cemetery, you can see the actors' shadows on the fake sky.
Deliberate mistake: In the alien spaceship, Eros speaks of the "Solarminite", Jeff Trent calls it "Solinite" and Col. Edwards calls it "Solar-inite". (01:05:55 - 01:07:50)
