Factual error: When Glen and Nancy are talking on the bridge, you can see a huge palm tree in the background. Springwood is supposed to be in Ohio - they show a map in 'Freddy's Dead, the Final Nightmare' - there are no palm trees in Ohio. (00:52:00)
Suggested correction: Nightmare on Elm Street was originally set in Los Angeles, per Wes Craven's script.
Factual error: The moment Nancy's digital watch hits zero, her bedside clock rings waking her up. You cannot set an old, mechanical style alarm clock to go off with anything like that level of accuracy.