Revealing mistake: In the overhead view of the bus driving across the desert to Camp Greenlake the dust behind the bus is CG, and near the end of the scene the bus moves up in the frame and the end of the dust trail cuts off with a straight line.
Continuity mistake: In the scene where Madame Zeroni is explaining to Elya Yelnats about the curse that will be bestowed upon him if he doesn't carry her up the mountain after presenting the pig to Myra's father, her blouse is a blue button-up with gold stripes and no collar. Then the camera looks at Elya, and then back at Madame Zeroni. When it looks back at Madame Zeroni, you can see that her blouse is now a gold button-up with a collar.
Continuity mistake: in the scene where Mr. Sir gets angry at the boy who said, "What happened to your face?" he asks the campers if he looks good and you see D-Tent sitting in the upper left hand corner, everyone is sitting down. In the close up of D-Tent, X-Ray and Armpit are standing then. In the next shot with Mr. Sir, you see Armpit and Magnet going to sit down. Then back to Mr. Sir, you see X-Ray standing.
Continuity mistake: In the scene where Trout's gang burns the school and kills Sam, there is a part where Katherine runs into the sheriff's office then exits. A few seconds later, Katherine runs by a shop on which the name is reversed. Very obvious.
Continuity mistake: When Zero runs away we see Stanley touching his hat, but when the camera goes to a further angle we see Stanley not touching his hat.
Continuity mistake: When Stanley finds the lipstick tube of K.B., X-Ray takes the tube then Stanley stops him. We see two angles (in front and behind) and Squid keeps changing his spot from left to right every time we see a new angle.
Continuity mistake: At the beginning when Stanley is digging his first hole, he has gloves in some shots and doesn't in others. (Specifically when he's complaining about the other guys' dirt).
Continuity mistake: The cast even points this out on the commentary: At the camp, where the tents and cabins are, there are trees at times and sometimes there aren't.
Deliberate mistake: When Kate Barlow shoots the Sheriff, she shoots him between the eyes, but when she kisses him there is no hole or anything on his face.
Continuity mistake: When Mr. Pedanski is explaining Camp Green Lake to Stanley, X-Ray, Armpit, and Squid come. Then right before X-Ray says, "Go ahead Pit" there is a shot with Mr. Pedanski and Stanley and there are two boys walking together. Then when we see Stanley and Mr. Pedanski again they're gone only for one boy.
Continuity mistake: Trout Walker has a gold tooth. In the scenes where he is wealthy it is on the left side of his mouth. In the scene where he is poor and dusty, pointing a gun at Kate, it on the right side of his mouth.
Continuity mistake: At the end part, when the kids at Camp Green Lake go dance in the rain, we see Zero looking up and his hair is in the air. In a different camera angle, his hair is put down by the rain. But when the camera returns to him looking up, his hair is up again.
Continuity mistake: When the boys are surprised that Zero talked we see Armpit and X-Ray. X-Ray is holding food, but in the next shot he's just making a fist.
Continuity mistake: In the scene where Stanley and Zero are digging to find the chest toward the end of the movie, the background behind them is just a dirt wall. In a following shot upon discovering the box, there are stairs that lead to the hole. In the next shot, these stairs are gone again and it's just the hole again.
Continuity mistake: In the scene when Zero and Stanley get to the top of God's Thumb Mountain, Stanley splashes Zero with some of the muddy water. Zero goes from having no mud on him, then having mud on him (before even getting in the water), to only having mud on his back (before getting in the water), to having mud on him (after in the water), to finally having no more mud on him (after being in the water).
Continuity mistake: In the scene at the end where the Yeltnats open the chest you can see Stanley's father with rubber gloves on, he takes his left glove off to look at the stock papers. You see him with his right glove on still, then Stanley takes one of the papers from his father and he doesn't have any gloves on, and in the next shot he has it back on his right hand.