Revealing mistake: A boulder tumbles towards James Mason and his party though a cave. With all the smashing against the walls and floor of the cave, the boulder stays entirely intact. However, just before the boulder hits a wall with two tunnels while flying through the air, the boulder now shows two majors fractures that were unseen earlier. The fractures were added to the boulder to give it a more dramatic impact by it breaking up with one piece nearly striking James Mason. (00:55:50)
Revealing mistake: Arlene Dahl hangs on to a stalactite as the water rises in a cave. At the ceiling you can see it swaying and breaking apart but the portion the woman holds doesn't move at all. (01:10:40)
Revealing mistake: Pat Boone gets lost. He walks over to a rock bridge, over a phosphorescent lake, which breaks up just before he steps on it. The larger chunk begins to fall but stops and bounces back up a bit because it hits a stage. (01:13:30)
Continuity mistake: James Mason meets the villain (Thayer David) who holds a gun on Mason and the rest. Mason outwits him by throwing salt into his face to blind him. When the salt hits his face, he closes his eyes (too early) before impact. The salt impact hits the right side of his face. An angle change occurs and we see a close-up of him (or a stunt double - his hair is different) and the salt hits the actor squarely in his face with his eyes open to the last microsecond. The scene changes back to show Mason and the villain with the salt on the right-side of the villain's face again with him in agony. (01:24:20)
Continuity mistake: Pat Boone was shot in the right arm by the villain. After a few scenes, his wound is gone - no evidence of an injury. (01:34:05)
Factual error: The Sun was shining quite brightly on the shores of the underground ocean (near the center of the Earth) as can be seen by the shadows of the actors. (01:39:20)
Continuity mistake: Arlene Dahl trips while running away from a dinosaur by stepping into a loop in a rope attached to a raft. Her foot snags it below the ankle near her toes. A few seconds later, you see a close-up of her and the dinosaur and now the rope is above her ankle. A few scenes later it's below her ankle again as the men come to her rescue. (01:42:10)
Visible crew/equipment: A diary flies out of Mason's hand while they are on a raft because of Earth's magnetic field. You can see a wire attached to the left corner of the book. (01:43:55)
Continuity mistake: After the villain (Thayer David) kills a duck, a boulder begins to move and brushes the side of his right leg as seen in a close-up and both legs can squarely be seen as he is standing beside the rock. The scene changes to a stunt-man who has his left-side towards the camera and this time his right leg is closer to the boulder which pushes him over a ledge. (01:50:35)
Revealing mistake: A giant lizard is stepped on by Boone. The lizard's skin turns red after being stepped on. It becomes so red that a nearby rock begins reflecting the red light. (01:55:40)
Visible crew/equipment: A giant lizard grabs hold of Mason with its very long tongue. Cables can be seen around the fake tongue which are both wrapped around Mason's left leg. (02:00:10)
Revealing mistake: As Mason's party rides a giant offering bowl (on magma) up a volcanic vent, you can see a straight seam joining the tubular vent on the bottom portion of the screen. (02:02:30)
Revealing mistake: Pat Boone falls out of a tree naked. But he is wearing skin-colored foot thongs on his feet so he won't cut himself while walking away from the fallen tree branches that were holding him. (02:04:50)
Factual error: Iceland sure looks a lot like the California desert.
Continuity mistake: In the beginning Professor Lindenbrook places his mountain goat horned ink well out of the way behind some scales, any other scene after that, they are missing.
Revealing mistake: When the first dimitridon (the sail-finned dinosaurs) shows up, the dimitridon's face changes color from the wide shot and the closeup of it and the Professor and the Count because of bad matting effects.
Revealing mistake: The actors get somewhat ragged as they spend months traveling towards the center of the Earth. But all of them are quite well shaven and their hair seems to never grow. Arlene Dahl's hair does have one curl out of place as they approach the center of the Earth. All of their hair gets wet and shaggy near the end of the movie.
Revealing mistake: Right before Alec nails the spike into the giant lizard's tongue, the blood bag he punctures is visible in the tongue.
Revealing mistake: When the group brings their raft out of the cave to the seashore, a dimitridon (the sail-finned dinosaur) attacks the group. Hans throws a spear into its mouth, and it dies, allowing the group to run the raft out to sea. We see several other dimitridons feasting on the dead one on one side of the screen, and the group sliding the raft to the sea on the other side. The sand on one side of the screen is a drastically different color than the other, one color ending abruptly and the other starting just as abruptly. That's 50's matting effects for you.
