Continuity mistake: When Alan drops the dice, after being startled by the clock chimimng, one die reads 3, the other 2. Yet when his board piece starts to move, you can see both of the sides of the dice, both reading 2. (00:13:25)
Continuity mistake: In the store, Hunter Van Pelt shoots his gun and hits the side of the tyre shelf, making a nick/hole in the red paint. The size and shape of the nick/hole changes between the two closeups of it, before the chain snaps and releases the tyres. (01:09:25)
Continuity mistake: During the scene when Alan is trapped in the quicksand, and the others are giving him items to hold onto, you can see behind him, to the viewers right of the blue chair in the background, a small stack of newspapers. But in later shots, such as after Peter runs out of the attic to go to the shed, and we then see Judy crawl over and grab the wooden music stand, to hit the spiders, the stack of newpapers has vanished, and a few other items change position, like the tennis racket. (01:20:55 - 01:23:00)
Continuity mistake: As Mrs. Thomas is being taken from her car, after being bitten by the mosquito, the men put her on a pedestal and you can see she is wearing long green boots that nearly reach up to her knees. Yet when they are putting her into the ambulance, she has black heeled shoes on. (00:37:50)
Continuity mistake: In the attic, Peter takes the Jumanji pieces out of the compartment, then closes it. Then when he takes the dice out the compartment, the compartment lid is open, not closed, and no-one touched it. (00:24:00)
Continuity mistake: After Sarah and Alan have been embedded into the floor by the quicksand, she rolls the dice with her teeth onto the board that's been propped up on Alan's face. The next time we see the board, when Peter's fighting with the spiders, the board's completely flat on the floor, when Alan's head should be propping it up. There's no angle between the main board and the two halves that fold out, but they are bent downward in the previous shot. Also, after Alan moves the board, at first it's relatively perpendicular to his face. Then, a few shots later when the spiders are retreating because of the impending earthquake, the board's rotated 45 degrees and moved farther away. It wasn't moved by rumblings from the earthquake- this is before the ground actually begins to shake. (01:28:15)
Continuity mistake: When the pelican grabs the game, there's a wide shot of Alan running behind the bird. The damage on the side of the arch behind is bigger than it was in the immediate previous shot.
Continuity mistake: When the monkeys go into the police car, they take the shotgun and fire it through the roof destroying the roof lights, but in all the later shots of the car the lights are still destroyed, but the roof shows no damage.
Continuity mistake: When the monkeys are in town looking at the electronics store TVs, there is no sun in front of the store. Once the angle changes to a front view, the sun is now shining where the monkeys were standing in shadow before. (01:05:15)
Continuity mistake: After being startled by the grandfather clock, Alan drops the dice on the board. Between a wide shot and a close-up of the board, the location of where the dice fall changes greatly. They have also moved when Alan gets sucked into the game. (00:13:20 - 00:14:15)
Continuity mistake: After the stampede, Alan runs off, then so do Sarah and Peter, and then the phone rings, so Judy answers it. Down the hallway you can see a chandelier, barely swinging. Yet when it cuts to Judy answering the phone, the chandelier is swinging much more violently. (00:57:35)
Continuity mistake: In the kitchen Alan opens the fridge and the monkey runs out. Judy is standing there and both her plaits are hanging behind her. In the next shot they are both hanging over her right shoulder. (00:41:25)
Continuity mistake: When the cop's car windshield gets destroyed, he says, "my car, my car..." When he's driving Alan, more of the glass is there.
Continuity mistake: Throughout the day the sun seems to go from an afternoon dusk sun when Van Pelt returns to the house, to an overhead sun during the stampede in town. It also goes from overcast and cloudy to clear cloudless sky with sun from shot to shot. (01:02:30)
Continuity mistake: When Alan's dad enters the car, he turns it on, yet you don't hear the engine start. When he shifts gears, you finally hear it start. (00:11:15)
Continuity mistake: In the supermarket, right before Peter spills detergent on the floor there's a shot of his feet walking by a shelf. The corner of the shelf is spotless, yet a frame later, from a wider angle, it's all covered with garbage.
Continuity mistake: While Alan is handcuffing Carl to the police car, the sky is clear and the sun is shining from the left (driver's) side of the car (indicated by strong shadows). As Alan is tossing the cuff keys away, the camera cuts to a view of the back of the police car which was shot on an overcast day, with the shadows very muted, and the sun coming from the car's right side. The view cuts again as Alan turns to run back to the police car, and we're back in bright sunlight from the left side. A couple shots later, as the car is reversing into the quick U-turn, the sun is shining from the car's right side again, this time with strong shadows. (01:09:30)
Continuity mistake: When Alan explains who he is to Sarah, she peers out through a door that's only open a crack. But when the shot cuts to Alan, his entire head and practically both his shoulders are visible through the door. When it switches back to Sarah, Alan appears to be at least two feet away (since he's totally out of the shot) and the door is still open the crack of a few inches. (00:47:20)
Continuity mistake: When Robin Williams and the cop are driving to the store in the cop car after the windshield was broken, neither of their hair is messed up and they can see clearly. (01:12:50)
Continuity mistake: When the LeBaron gets hit by the ambulance, we see that it comes to a stop about 10-15 feet from the corner. When the paramedics come out to help the woman in the car, it is now right at the corner. (00:38:50)
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.