Factual error: In the scene where Bobby and Mike go into the comic book store, you can clearly see a Transformers comic on the shelf. But the movie is set in the late 1960's/early 1970's....and Transformers did not come out until the 1980's.

Continuity: As the boys are running through the sewer tunnel, both of them fall several times, and they are covered with dirt and sewage. When they come out and face the bullies, their clothes are clean.

Factual error: The walkie-talkies the kids use at the end of the film would not make the squealing noise they do. The walkie-talkies they have transmit on high enough frequencies that this would not happen. Mediumwave and Shortwave have this effect, not walkie-talkies.

Continuity: When the family moves into the new house, the father rips the former owners' name sign off the front of the house. A few shots later, it's back.

Continuity: At the end when Mike receives the first postcard from Bobby, the flag on the mailbox is up, meaning there is mail to be picked up by the postman. Then when he takes the mail out and runs towards the house, the flag is down without him touching it.

Revealing: After Mike has come home from being beaten up during a game of football, there are no longer open wounds by his mouth and nose, and the dried "blood" looks more like Kool-Aid stains.