Revealing mistake: When Francis emerges from the cave, he stands in the foreground, with the distant mountains and sun in the background. The sun creates a lens flare, which is an internal reflection within the camera lens. Yet Francis is in front of the flare. This shows that the actor was composited with the background via a traveling matte process.
Revealing mistake: In the carousel scene, when the contestants are starting to float into the air, you can see the cables attached to the contestants that are lifting them up. (00:08:58)
Continuity mistake: At the end of the film, when everyone is gathering around the old man, there are several close up shots of him. In one of them, a woman in pink starts walking up behind him, near the right side of the screen. In the next shot, the camera shows a faraway view of the old man and where the woman was standing, but she is gone.
Continuity mistake: In the scene where Francis looks at his palm and sees the crystal is clear, he jumps off the balcony towards Logan but you can tell from the jump angle, he will not make contact with Logan, being some 3 feet from the landing point. In the next shot, Francis lands right in front of Logan. (01:30:40)
Continuity mistake: When Logan and Francis chase the first Runner around and up the balconies inside The Great Hall, it seems as though the chase starts on the ground floor and only goes up one floor. But, when Francis shoots the Runner, he falls from about seven floors up, a long, protracted fall.
Revealing mistake: When the dome city starts to blow up, people are running around in a panic. One man in a red outfit jumps off a balcony to the next floor and you can see a modern (1970s) lit exit sign over a doorway behind him. Many of the interior shots for the dome city were filmed in a large shopping mall; that sign must have been missed when they were trying to make it look like the year 2274.
Continuity mistake: In the scene at the end with the old man, his fire is burning well but suddenly is almost burned out when the people come down to see him.
Plot hole: In one of the late scenes Logan is interrogated by the mainframe computer, and is guarded by two other sandmen. No one in the city is allowed to be over thirty years of age, yet the guards are at least in their late 30s or early 40s.