Continuity mistake: When the hunter fires at the cop (with his old gun) he fires once and the cop ducks behind the car. We see three bullet holes in the car when there should only be one. (00:56:15)
Continuity mistake: The licence plate on Carl's car is "G2298" but after finding the car which the monkeys had smashed into a tree, as he reverses, the plate is "DBA 454." (00:50:30)
Continuity mistake: When Alan is eating dinner, and his father is shouting at him, the fork and knife on Alan's dinner plate moves around between shots. (00:09:40 - 00:11:00)
Continuity mistake: During the rampage through town, the driver of a red Ford parks and then runs out in panic. In one shot, the license plate number is AZP-281. In the next shot, it is SLP-281. (01:07:16)
Continuity mistake: After Judy is shot by the poison flower, Peter cradles her in his arms. That is in close-up. When it goes to wide shot, he isn't cradling her anymore.
Continuity mistake: After Alan swings on the rope and grabs the game he opens it and suddenly hears the hunter say "Don't move." During those shots the position of the pieces on the board are not continuous.
Continuity mistake: When the house is breaking in two and the floor swallows Alan, the damage to the round window is not continuous between the shots inside and the angle shot from outside.
Continuity mistake: When the movie ends and Alan becomes young again he hugs his father. The position of the handkerchief on his suit changes between shots.
Continuity mistake: When Judy is fighting off the spiders, the floor breaks and a purple plant comes out of the floor and shoots her in the neck. You can see the barbs, but in the next shot when her brother starts running toward her, they magically disappear, and in the next shot they appear again. (01:30:30)
Continuity mistake: In the scene in which an ambulance wrecks the back of Judy and Peter's realtor, the license plate on the front of their car reads DBA-454. However, in the scene where Carl finds his car wrecked into a tree, when he backs out, his license plate also reads DBA-454. (00:38:50 - 00:52:35)
Continuity mistake: When Peter sets the Jumanji game on the table for the first time, it is placed sideways in the wide shots, or parallel to the table in the close-ups.
Continuity mistake: When Alan confronts the lions, he stabs the knife on the floor facing a 4 o'clock position. when the angle changes it faces 6 o'clock.
Continuity mistake: When Peter's foot is trapped by the carnivore plant and is held up by the 3 guys, his jacket is alternately hanging loose or stuck under Sarah's arm.
Continuity mistake: When the cop is about to run Alan over with the car, first Alan is standing sideways on the road, then there's a close-up of him turned 90ยบ looking straight at the cop, then a third angle shows him turning around from the initial sideways position.
Continuity mistake: When the spiders show up, Alan's hair is covering his right temple or not, depending on the angle. This changes back and forth.
Continuity mistake: When the hunter crashes against the supermarket wall it makes no mess - as the final wide angle reveals, yet when the kids arrive the whole place has stuff scattered all over.
Continuity mistake: When Alan is about to cry "stampede!" several books fall on the floor. After he shouts it, there's a wide angle and the books are gone.
Continuity mistake: Peter says he only needed a 10 to win. Impossible. He has only rolled a 2 and 5 (in the attic).
Continuity mistake: When the cop is about to encounter Alan, there are two passers-by behind the car who disappear in the close-up angle.
Continuity mistake: When Van Pelt shoots the tire shelf in the store, the attached red wood triangle support is actually different between shots - note paint and dings. Furthermore, dirt marks on the tires appear, and two of the slotted heads of the screws, that are screwed into the anchor eye plate, are turned facing opposite directions (before it breaks). (01:09:25)
Answer: The game is essentially "resetting reality" back to the point Alan was first sucked into the game. So it is undoing everything that has been done - including taking away the gun and bullets Van Pelt had purchased.