Continuity mistake: After Dennis has stolen the embryos, when he reaches the first gate he gets out of the Jeep then uses the manual override to unlock the gate, and in the exterior shot when Dennis walks back to the Jeep his door is wide open, but in the next interior shot his door's closed and he even has difficulty opening it.
Continuity mistake: In the scene with the T. Rex breaking through the glass roof, as the glass breaks one of the rex's front teeth breaks off and flies backward. On the next close-up of the dinosaur's mouth, the tooth is still missing, yet it is back in all shots after that.
Continuity mistake: In an early scene, Samuel L Jackson's character is struggling to get the computers up, and he is smoking away. A full cigarette, then half, then full, all without lighting a new smoke. (00:56:25)
Visible crew/equipment: In the scene where Grant and Lex are hanging from the fence cables on the wall in the Tyrannosaur paddock they start swinging back and forth to avoid the truck that is about to fall on them. Look closely in some of the closeup shots, you can see that the cable that Grant is holding on is actually a safety rig. The harness straps are visible.
Continuity mistake: The satchel of money Nedry receives as a down payment for getting the embryos off the island vanishes from his arms as he looks at the false container of shaving cream. It vanishes mid-sentence; he had no time to put it down. (00:14:00)
Visible crew/equipment: When the two Explorer vehicles begin the tour and drive past the huge automated wood doors, if we look at the area between the two doors just as the doors are shut we can see someone's arm come down from behind the door on the right, presumably to keep both doors properly closed for the shot.
Visible crew/equipment: In the kitchen scene, when the raptor appears in the small window. You can see movement (possibly a reflection of a camera person's arm) on the surface of the door, right below the window. (01:43:45)
Other mistake: Hammond has a pronounced Scottish accent at the start of the film, which deteriorates markedly in just a couple of scenes. By the end of the film he has an upper class English accent. (00:09:50)
Revealing mistake: In the opening scene Jophery is being attacked by the velociraptor. As the camera pans along the outside of the cage, in between the flashes one can see his legs inside the cage and that nothing is actually attacking him. (00:03:05)
Continuity mistake: Right before the T. Rex breaks out of the paddock there's a shot of the back of Explorer 4, and the rear windshield wiper is gone, but it reappears, vanishes, and then reappears again during the T. Rex attack.
Continuity mistake: When the T. Rex escapes its paddock and then Tim tells Lex to turn the light off, in the interior shot after Tim closes the vehicle's door, the plastic piece (used for seat belts) anchored to the panel between the windows vanishes inexplicably leaving just a hole, and when the T. Rex roars Tim covers his ears and there's some kind of small plastic on that hole.
Continuity mistake: After Alan pulls Lex out from the overturned Explorer and the T. Rex spins the vehicle around, in the closeup shot from behind Tim while he's still inside the Explorer, as the T. Rex leans down facing Tim we can see one of the lower front teeth is missing, but it's back in the following shots.
Continuity mistake: In the Badlands scene, when Dr. Grant enters the trailer there is a large overhead shade blocking out direct sunlight. On the inside light is streaming through the windows. On top of that, the first window is larger when seen inside the trailer than it is when seen from the outside. (00:09:50)
Continuity mistake: When Tim, Lex and Dr. Grant are hiding in a large tree, a large dinosaur appears. They pull some branches off the tree and feed the dinosaur. However, when they first climb the tree, there is no foliage in the area at all. (01:19:20)
Continuity mistake: When the two kids are eating the food just before the raptors try to attack them, the little boy's hair is all messy and strands of it are sticking out. In the next scene, when the kids run into the kitchen and hide behind the counter, his hair is perfectly straight and combed. (01:43:30)
Factual error: In the early scene where Dennis Nedry meets a man to plan the embryo theft, the subtitle says that they are in San José, Costa Rica. However, the sleepy coastal town in the movie within sight of the ocean bears no resemblance to the real San José (a cosmopolitan capital of almost 1 million people, situated 50 miles from either coast). Even the book makes this error. (00:13:10 - 00:14:45)
Revealing mistake: When the Explorers are entering the park through the large wooden gate, during the overhead angle you can see that the perimeter fence isn't continuous. (00:40:00)
Revealing mistake: When Tim is looking at the 2 cups of water vibrating due to the T-Rex's stomping, you can see a very small dark spot at the bottom of the cup, which is actually the knot of a guitar string that was plucked to create the vibration effect.
Continuity mistake: When Nedry is trying to escape, and his jeep gets stuck on the mud bank, the camera shows the road below him, and there's an arrow pointing straight ahead. A bit later, the camera shows it again, and the arrow's now pointing left. (01:08:20)
Visible crew/equipment: When Lex & Tim are hiding from the two raptors in the kitchen, a ladle (a soup spoon) by Tim's head falls to the floor and attracts the attention of the raptors. If you watch the top of the ladle right before it falls, from the right you can clearly see the shadow of the device that causes it to turn and fall. (01:45:55)
Chosen answer: They all left on the same boat Nedry was trying to get on with the embryos. You can hear Samuel L Jackson's character announce that the boat will be leaving at a specific time and everyone had to be there or be left behind.
Shannon Jackson