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?
Other mistake: When Scott is delivering the hardware store supplies for the play, the cans of paint he is carrying awkwardly flip about like empty ones, and when he drops it makes a hollow sound. I'm sure they are meant to be full.
Continuity mistake: When Scott turns into the wolf for the first time in his bathroom, the position of his blue coat on the toilet seat keeps changing.
Continuity mistake: At the very end, Pamela tells her boyfriend to drop dead and walks away, off to her right. But in the last shot where Scott is hugging his girlfriend and his dad, if you look just to the lower left of them, not only is Pamela still just standing there, but she's to the left of where she was standing before.
Visible crew/equipment: When the wolf is "surfing" on top of his van, he does a hand stand, and you can see the handles he's holding onto for balance. They aren't there when they are surfing standing up. (01:00:15)
Factual error: There are no palm trees in Nebraska, visible when Wolf Scott surfs the Wolfmobile. (00:59:45)