A woman is killed by monster at the start of the movie, even though the person in question hasn't transformed into it yet.
In the "where are they now" wrap-up, 'museum' is misspelled.
The Sherriff's son takes over his role after he is killed even though he doesn't work for the Sherriff's dept (he's a lifeguard). He takes over the investigation and takes charge over the deputies. This would never happen in reality.