Plot hole: Isn't it rather strange that nobody outside the Howard family's small town expresses any interest in the confirmed discovery of a new human sub-species, the only one on the planet? Wouldn't it be more likely that their little backwater town would be inundated with every press and scientific organisation on earth, and that the Howard family would be the centre of the greatest publicity carnival of all time?
Visible crew/equipment: When Pee Wee is chaining up his beloved bike you can see the long chain coming up through the bottom of the bike box. Full screen version only. (00:13:40)
Continuity mistake: Near the end of the movie, when Parker and Hunt are on the bus going to the contest, you'll see that Parker's hair is in waves. But when she arrives at the studio, her hair is VERY curly. Its not likely that she had time to change her hairstyle THAT drastically if she was pressed for time as she very clearly was.
Continuity mistake: Towards the end of the film, during the chase scene between the newspaper boy and Lane, you can see the skis of the camera guy.
Other mistake: When Chevy chase is being filmed cheating on the exam, all the video cameras are on the sidewalls near the roof. But later when they view the footage, the last shot of Chevy copying the answers is from the floor level where no camera was seen in any previous shots. Also what was a floor level camera going to film anyway...everyone's feet?
Continuity mistake: When Fletch and Stanwyk first meet and Stanwyk asks Fletch to come to his home and hear his proposal, Stanwyk is wearing a suit/tie on top but is wearing jeans on the bottom. In the next wide shot as they leave the beach, and again in the next scene as they arrive at Stanwyk's house, he is wearing suit pants. (00:04:50)
Audio problem: In the beginning of the movie when Clark is preparing to light the Bar-B-Q, He squirts charcoal fluid out of a plastic bottle. Then Ellen squirts more fluid onto the coals out of the same plastic bottle. Listen to the sound; it is the distinctive sound of a metal charcoal lighter fluid bottle. (00:07:45)
Other mistake: When the fake TV ads for the Stuff are shown, the container states "1 Pint (.474ml)". 0.474ml is about an eyedropper drip of liquid. The decimal point shouldn't have been there.
Plot hole: When Diana turns up at her director friend's house she finds it crawling with cops as his girlfriend Christie has been murdered and the house is now a crime scene. She explains she lent Christie a coat and is there to pick it up - and a cop helpfully finds it on the floor and hands it to her. Are we to believe that a homicide policeman will hand over an artifact from a murder scene to an unidentified woman without making any attempt to confirm her identity, or even if the coat is even hers!? They don't even ask.
Continuity mistake: When the evil spell takes over the tree in the Forest of Feelings, Brave Heart Lion has his symbol on his belly in the shot as Swift Heart rabbit is coming to the rescue. They don't get their symbols until the end of the movie. (00:41:05)