Continuity mistake: During the mailbox baseball scene, Ace is shown with a cigarette in his mouth. Then after he strikes out and says "ah shit, I'm out", the cigarette is gone.
Factual error: When they find the dead body, the body looks like it has been dead for only a short while, his face even had a pinkish color to it still. Factually, the body would be a lot more decomposed after a few days, bluish or white in color from the blood pooling at the bottom of the body, since the body was on its back. (01:08:30)
Continuity mistake: About half way through their journey the boys clothes are very dirty, then they become spotless.
Visible crew/equipment: In a bird's eye view when the boys cross the bridge, there is a camera visible at the end of the bridge.
Revealing mistake: During the pie eating scene when the projectile stream of blueberries starts, the alignment is off for most of them, as it appears to come out of their noses and chins as well. The pie eating contestant next to the radio personality has their stream fall in an arc until it looks like it's coming from beneath their chin directly downward.
Revealing mistake: When Lardass is getting ready before he comes up onstage, listen closely when he drops the egg into his mouth, and you'll realise that it isn't going into his mouth, it is landing on the ground. You can tell, because you can hear it hit the ground.
Continuity mistake: The author in the beginning is supposed to be Gordy grown up, but the grown up Gordy has blue eyes and light hair color and Gordy as a kid had brown hair and brown eyes.
Revealing mistake: When Ace runs the truck driver off the road, it's obvious that Ace Billy and Charlie are stunt doubles, because of the hair and age.
Continuity mistake: In the beginning scene, the newspaper clipping under the headline shows the first sentence to be about Chris' death from a stabbing, but the next line starts mid sentence about a completely different subject and the second column under the headline talks about taxes, mentioning nothing about the death.
Continuity mistake: When the boys are in the treehouse at the beginning, the coca cola bottle on the treehouse shelf constantly moves places between shots. The two sides of the bottle saying "coke" and "coca-cola" keep switching positions between shots also. (00:02:55 - 00:04:55)
Revealing mistake: When Davey cracks the egg, you can tell he doesn't crack it into his mouth. It slides down his cheek and hits the ground. You can actually hear this happen.
Factual error: There's a scene with a house in the background that has the electric wires from the power pole going to a connection above the roof. In 1959, the connection would have been made under the eaves or on the outer wall.
Factual error: When the boys first start their hike at the railroad yard there is a modern transformer on a pole in the background. In 1959 they were smaller and black. (00:15:00)