Continuity mistake: As Miles and Sally drive away from the train station her hand is resting on the passenger side window. In the very next shot her hand is by her side. (00:03:40)
Other mistake: Before Becky and Miles go down the steps after leaving his office she says "I've been in Reno". The camera goes totally out of focus for a second right when she says, "Reno" the second time. (00:07:10)
Continuity mistake: As Miles walks from the train in the long shot he gets money from his pocket with his right hand and is carrying his coat with his left. In the close-up we see he's holding the coat differently and has the money in his left hand. (00:02:50)
Visible crew/equipment: In the beginning of the movie as the two doctors walk up to it, equipment and lights are seen reflected in Dr. Bassett's door. (00:02:00)
Continuity mistake: Miles' car is parked very close to the white car, but in the shot of uncle Ira mowing his lawn it's not there. (00:12:45 - 00:14:10)
Continuity mistake: In Becky's basement Miles lets the match that he lights burn right up to his fingertips but when he puts it out the light remains on him for one or two seconds more. (00:29:50)
Continuity mistake: After they find and fingerprint the alien body on the pool table, Jack starts out holding the piece of paper with the blank fingerprints on it in both hands. In the next shot he's holding his pipe in his right hand. (00:21:35)
Continuity mistake: It's supposed to be a duplicate, but the cut on the body that's on the pool table's hand is in a different position that when we first see it on Jack's hand in the earlier scene. (00:25:50)
Continuity mistake: As Miles slams on the brakes so that he won't hit Jimmy Grimaldi Sally is seated to the left of him in the passenger seat. In the shot from the front she's seated in the middle of this seat behind the rearview mirror. (00:04:15)
Visible crew/equipment: As Becky and Miles part company, after crossing the street, you can see the reflection of a camera man in the window to the left of the Flint Ware sign. (00:08:15)
Continuity mistake: On top of Miles' stove when we first see the coffee in the coffee pot its three quarters full. Later we see it again while Becky is poring Jack a cup of coffee and there's less and she didn't touch it. (00:36:55)
Audio problem: As Becky and Miles go down the steps after leaving his office. Miles keeps mouthing something after we hear the dialogue stop. (00:07:20)
Continuity mistake: In the first shot of the movie there's an equipment shadow on the door of the police car as the policeman opens it. (00:01:30)
Visible crew/equipment: As they drive there's a moving equipment reflection in the windshield by Miles' hat as Sally says "That fat traffic cop". (00:03:50)
Continuity mistake: As Miles wonders why the body is in the house, Jack goes from looking at Miles to looking at the body between shots. (00:23:30)
Continuity mistake: In Miles' kitchen, Becky never turns the stove on to boil the eggs. The burners are not on and when she comes back from looking in the basement she moves to turn the stove off. (00:36:30)
Continuity mistake: As Miles begins to talk to the doctors in the restaurant parking lot he's leaning into the car. In the next close up shot his position has changed and he's not leaning into the car. (00:15:35)
Plot hole: When Becky falls asleep she is awakened by Miles and has now become an alien, However she should have died and her essence should have been in one of the pods. There were none nearby.
Audio problem: When Miles and Becky are in his office trying to figure out how to get out of town, Miles says "Our only chance is to get to the highway." However, if you watch his mouth, it's clear what he actually said was "Our only chance is to get to the freeway." This was presumably changed for a wider audience. The film takes place in California, and in the 1950s "freeway" was used in California, but most of the rest of the country used "highway."
