Continuity mistake: When Alan is trapped on the floor, and the game is placed over his head, Sarah rolls the dice which fall on the lower left corner. When the angle changes they've moved further to the right.
Continuity mistake: When the Aunt flags down the cop car, the cop has his seat belt on, as the plant starts coming in the car to grab him and the car. He jumps out of the car without ever undoing his seat belt. (01:14:45)
Continuity mistake: When the insect sits on the windowshield of the car Robin Williams says that the insects can't make a hole, they are safe, then the insect makes a hole, the car drives away creating havoc on the road because of extreme bad driving. The car stops, they get out, then there is no hole in the windowshield. (00:40:10)
Continuity mistake: Carl's cop car has the licence plate "G2298" which is printed thinly on the licence plate. Then, when the vine wraps around his car, and bends it in two, the licence plate is now "CFJB95", printed very boldly on the plate. The words "POLICE 004" also differ, as does the bumper and the lights. Totally new car, methinks... (01:14:55)
Continuity mistake: When Peter runs out of the attic to the woodshed to get the axe, to the left of the attic door is a large filing cabinet, with nothing in front of it or beside it. Yet later when Peter is swinging the axe at the spiders, and following shots, a green suitcase has appeared in front if it. (01:22:45 - 01:25:00)
Continuity mistake: When Judy is talking with Carl outside the front of their house as Alan examines the police car, Judy's pigtails are alternatively in front of, or behind her shoulders during shots. (00:33:00)
Continuity mistake: When the monkeys are destroying the kitchen the kids open the kitchen door and the monkey on top of the refrigerator knocks the cereal box to the floor. A few seconds later the cereal box is back on top of the refrigerator and the monkey knocks it over only spilling the contents. (00:26:45)
Continuity mistake: At the construction site, Alan claws through the mud, to get to the large metal box. His fingers get covered in mud, yet as he pulls the box out of the mud, and in following shots, the tops of his fingers and his fingernails are very clean. (00:07:00 - 00:07:50)
Continuity mistake: When Sarah, Judy and Peter are in the store, where the riot is going on, they spot the Jumanji Board Game sitting on the till counter. To the right of the till is a very large "Sand and Water Activity Table" box. In one shot the box it facing so you can see the upper part/top of the box. It then cuts, and the box has mysteriously rotated 180°, so that you can now see the lower part/bottom of the box! In the same shots, there is a trolley by the till, with some items and a box in it. Cut back to the trolley and there's now two boxes in it! It then cuts, and the box is back to it's original position, and the box in the trolley disappears! If you look more closely, the entire shelf unit behind the counter is completely different!!! (01:05:55)
Continuity mistake: When Alan is trying to get Jumanji back from the pelican, he grabs a fish from the water, and his sleeve becomes soaking wet. In the next shot his sleeve is bone dry. (00:59:05)
Continuity mistake: In one of the closeups of Alan sitting in the car as it is crashing through the displays inside the Sir Savalot Store, the background, visible through the driver's side window, is of open fields, trees and blue sky. (01:13:00)
Continuity mistake: When Peter rolls the dice prior to letting the monkeys loose, whilst him and Judy are in the attic, he rolls both "1"'s. The sides of the dice which are visible read "3" on one die and "4" on the other. Then when it cuts to a closeup of the boardpiece moving, the "4" now reads a "2", and the dice have also moved position. (00:25:15)
Continuity mistake: When the monkeys are causing chaos in the kitchen, a monkey throws three knives at the kids. Two of them stay in the door, but one bounces off and only makes a nick in the wood. Later in the film, when Robin Williams is in the kitchen, and he blocks the door, you can see that the two knives that were stuck in the door are still there, but the nick in the wood has gone. (00:27:10)
Continuity mistake: When Van Pelt comes out of Jumanji, he starts shooting at Alan. Alan then runs through the brown doors, and Van Pelt shoots, misses, and blows a large hole into the door. Yet when they all return to the room, the hole in the door is smaller. (00:53:20 - 00:55:25)
Continuity mistake: When all the monkeys are in the kitchen, Judy and Peter open the door to peek inside, and a monkey throws a tomato at the kitchen door, making a big stain of tomato juice on the door. When the monkey throws the knives at the door though, the stain has vanished, and the door is clean. (00:25:55)
Continuity mistake: After Peter discovers the bat in the attic, he runs downstairs screaming, and you can see a chair by the door of the attic with a white cloth sitting on it. However when Aunt Nora walks upstairs, there is no sheet on the chair. (00:18:00)
Continuity mistake: When Alan confronts the lion with a knife, the blade is either facing flat or sideways depending on the angle.
Continuity mistake: After Alan traps the lion in the bedroom, it makes claw marks in the door. The marks change greatly from the first close-up of them being made, to the second shot when Alan walks away from the door. (00:28:35)
Continuity mistake: When the earthquake begins, the floorboards start to break in two, and Alan starts falling so Sarah holds onto him. Watch the small circular window in the wideshot. (the window that the mosquito flew out of earlier in the film) To the left of the circular window are some empty wooden beams, but no items. When it then cuts to a closeup of the window breaking in two, items have appeared on the beams, and there's a banjo hanging up etc. (01:25:30)
Continuity mistake: During the stampede, when the four are watching the animals pass by the hall, Sarah is randomly next to Alan or behind him. Also, when the stampede ends, the four swap from being separate to firmly together in a mere frame.
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.