Visible crew/equipment: As Hadley stands near the lockers, talking to Larkin and packing, the boom shadow dips into the shot over his head. (00:28:35)
Visible crew/equipment: When the black Ford pulls up to Minns' apartment building and Ballard gets out, several studio lights and reflectors are mirrored in the car's shiny surface. (00:48:25)

Visible crew/equipment: At the start, when Ballard and Harris walk into apartment 17 to wait for Minns, just as Ballard is introduced to the others, the shadow of the boom mic drops down on the door, at the right side of the screen. (00:01:10)

Continuity mistake: In part 1 and part 2, the character that Donald Harron portrays is noted as "Art Harris" in the opening credits of both episodes. The problem occurs during part 2, where the character is repeatedly referred to as "Ray" Harris, the FBS Deputy Director. (00:05:15 - 00:05:50)
Continuity mistake: Ballard reports that 6 bullets were fired at Minns. He's a trained investigator, but he apparently can't count as well as the viewers can. We saw his men fire at Minns - 7 times. (00:07:40)
Factual error: Outside the warehouse, one of Ballard's men is talking on a car phone. We're not sure who he could connect with, though. The car has no mobile transmission antenna, and in the 60s, it would have needed a very large one. (00:26:00)
Visible crew/equipment: When Minns pulls up to get Johnny, the entire camera crew and several lights are reflected in the side panels of his station wagon. (00:32:00)
Revealing mistake: This episode's futuristic video-phones seem to be a production afterthought not in the original script. Consequently, Mrs. James talks to her husband's clone on the phone, but doesn't seem to see him on the screen. She tells James, "He sounded like you," and goes on about his voice, but never mentions his appearance. Later, her reaction to seeing both of them together indicates she's never seen the duplicate before - even though she has, on the video-phone. (00:25:00)
Revealing mistake: Janie is frozen in place on her tricycle, but the 5-year-old actress has a hard time holding still. She's visibly fidgeting. And when a freeze-frame of her is used for close-ups, there's a black blotch on the film over her neck. (00:26:30)
Continuity mistake: In the scene after the second crash, when the pilot and his wife "borrow" the jeep to return to the base, the shot is flipped, reversing the positions of the husband and wife in a mirror image of the real vehicle, placing the "driver" in the passenger position and the spare tire, which should be on the near side, is now on the far side. In the next shot, as the vehicle nears the base, everything suddenly resumes the correct perspective.
Revealing mistake: Indicative of previous takes, the floor inside the alien probe already has several human footprints all over it before the characters exit their life boat and walk on it. (00:10:00)

Visible crew/equipment: The shadow of the boom pole and mic are visible on the floor. (00:22:55)

Visible crew/equipment: The shadow of the boom mic is visible on the wall on the left side of the screen. (00:31:00)
Continuity mistake: When she's inside the giant test tube, Amanda raises her arms over her head. In the very next shot, with no time for her to have moved that fast, her arms are straight down and held rigidly at her sides. (00:36:15)
Deliberate mistake: Amanda survives a plane crash into the ocean, hurricane winds in a life raft, then experimentation and attacks by giant microbes inside the alien probe. Yet when she and the others are rescued at the end, not one strand of hair is loose in her 1960s "beehive" hairdo. (00:49:05)