Revealing mistake: Wile driving away from the dinosaur Malcolm tells the driver to go fast. The stunt driver is very noticeable - he has a bigger head and way more hair than the actor.
Other mistake: While being chased by a T-Rex, after it breaks a trunk the digital dinosaur runs behind the car. There's a couple of shots of the people in the moving car and the next time we see the dinosaur angle the background clip is the very same one used before.
Continuity mistake: When Grant nearly passes out after first seeing the Brachiosaurus, he sits down on the grass. In the following shot, he is shown kneeling.
Continuity mistake: After the kids have greeted Hammond, everyone is outside the building waiting to see the vehicles. In the first angle they are several meters to the right of the stairs. When the angle changes they have moved back and are standing closer together.
Other mistake: The kid who at the dig site in Montana says "That doesn't look very scary" is so far from the screen and behind all the other spectators that he can't possibly see the picture on the screen. And even if he could, it doesn't look anything like a six foot turkey.
Continuity mistake: In the scene with Dr. Grant and Lex standing nose-to-nose with the T-Rex, the dinosaur sniffs at the humans, then turns its attention to pushing the Explorer around as Grant and Lex scramble for safety. When the T-Rex starts pushing the Explorer, a profile shot shows that the monster's foot is no more than two yards from the vehicle; yet, in the immediate next shot from the monster's point of view, the T-Rex is obviously positioned 10 or 15 yards away from the Explorer, much too far away to be pushing the vehicle.
Continuity mistake: After the first T-Rex attack, Tim's rover is still stuck in the tree, and Dr. Grant and Lex arrive at the base of the wall adjacent to a gushing storm drainage pipe. Dr. Grant assures Lex that he will return and goes to assist Tim. Whimpering, Lex clambers up to take shelter in the drainage pipe. However, there is now an inexplicable blue light glowing from deep inside the drainage pipe, illuminating Lex.
Continuity mistake: In the final rotunda scene, when the rex is chewing the first velociraptor, there is a skeleton piece (a herbivore tail) hanging beside it. In the next shot, when the second velociraptor jumps rex, this piece of the skeleton is no longer there.
Continuity mistake: When Nedry hears the Dilophosaurus and turns around, he's holding a tow cable. It's gone in the next shot.
Suggested correction: Between shots you can see how he releases the winch cable before turning.
Continuity mistake: The T-rex completely destroys the outdoor bathroom facility that the lawyer ran into. The lawyer is perched atop the toilet and the remaining damaged wall behind him is tilted backwards. When the camera cuts to a shot where the lawyer is seen from behind and the T-rex is just about to eat him, the wall is missing. When it cuts back to a front shot, the wall is back again.
Continuity mistake: When the car with Tim and Lex is turned over, mud flows into it and it's like they are going to drown. But when seen from the outside, next to the tracks is a firm gravel road, and Dr. Grant doesn't even sink in when he steps out of his car with the flare.
Deliberate mistake: When flying towards the island, the sea in the background is way too close. A helicopter flying over open sea would never fly that low. And when the camera cuts to an external view, the helicopter is also much, much higher.
Continuity mistake: When Ian Malcolm jumps out of the jeep to wave the flare at the T-Rex, there is strange mark on his forearm. When he starts to run from the T-Rex, with his arm still in the air, the mark is gone.
Continuity mistake: When Lex saves Tim's life in the kitchen, she goes into shelter. When the Dinosaur chases Lex's reflection she is facing the dinosaur's face, but in the next shot her reflection has changed by 90°.
Continuity mistake: When the T-Rex escapes, the lawyer leaves the door open. Next scene, the door is closed. Then open, then closed again. Then open for Timmy to close it. Also, when the T-Rex escapes, he walks away between the trucks. The tail is already passed them. Then the girl turns the spotlight on, and the T-Rex is back to where it started. Hasn't crossed between yet.
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.
Revealing mistake: The two Jeeps running during the tour are supposed to be automatically moving along the track in the road but several shots reveal there is nothing connecting the Jeeps to the track.
Character mistake: Grant and Tim could simply have moved to the side of the tree instead of climbing down with the Jeep right behind them.
Visible crew/equipment: When Dr. Grant discovers the eggs in the wild, the camera comes down a tad bit too far. The operator obviously notices because the shadow of the camera creeps in along with the shadow of wires attached to it. To correct this, the shot pans up a bit.
Continuity mistake: Tim finds the goggles and puts them on. He climbs into the back seat and Lex watches him. The scene cuts to outside the car and Lex is looking forward.
