Revealing mistake: The red light from the camera is clearly reflected in the silver part of Sam's torch, as she reads her book in bed. (00:11:45)
Revealing mistake: After the Wormers attack the girls with Jell-O-bombs, Roberta runs after them, and then dives to the floor. Small flesh-coloured kneepads are visible on her knees. (00:16:10)
Revealing mistake: When the girls are looking at Sam's mum out of the window, Teeny (Thora Birch) briefy looks over at the camera. (00:18:10)
Revealing mistake: It is obvious that when Sam is in her bed reading her book with a torch, that a set light is being shone at her face and that the glow doesn't come from the torch, because she turns the torch away from her and puts it on the bed, but a soft glow of light remains on her face for some seconds. (00:20:20)
Revealing mistake: When Sam trips over in the cemetery, she falls onto Dear Johnny's cracked tombstone. As she pushes down, the 'tombstone' squashes under her hands. (00:27:25)
Revealing mistake: After Chrissy punches Roberta, there is a towel visible around Roberta's waist. (00:33:55)
Revealing mistake: When the Wormers are chasing the girls, who have stolen their clothes, as they run out from behind the tractor the boy holding the bucket in front of his private area moves it, revealing a really noticeable modesty patch he's wearing. (00:37:55)
Revealing mistake: When Sam discovers the pages have been torn out of the Shelby newspaper book, the exact same text is printed on each part of the torn page. (00:41:45)
Revealing mistake: When the girls are at the door of the fortune-teller, after Sam says "We need your help", Teeny (Thora Birch) looks at the camera. (00:48:10)
Revealing mistake: You can see the round stage/set lights reflected in Morton's glasses, when he jumps from the fence to go over to Chrissy during the softball game. (00:51:55)
Revealing mistake: At the dinner table, when Bud knocks the glass of wine over, and the wine spills all over his shirt and trousers, a large red wine stain is already visible on his white shirt, before the glass is even knocked. (00:55:25)
Revealing mistake: Sam and Teeny clearly look down at their actor marks as they walk to Sam's Grandma's door. (01:09:45)
Revealing mistake: After the girls have seen the boys skinny dipping in the pond and have stolen their clothes, the boys run after them. Devon Sawa bends down to pick up his underwear but you can see he has a flesh coloured "modesty pouch" on under his towel, when he is supposed to be naked.
Answer: Reshooting certain scenes would most likely necessitate new stunt people, as the first one(s) would most likely be hard to get back.