Other mistake: The date on the tombstone above Annie says that Judith Myers was born November 10, 1947, and died October 31, 1963. That would make her 15 (not quite 16 yet) at the time of death, yet everyone says that she was 17 years old.
Other mistake: In the aerial shots of the semis being driven in the mall parking lot, the zombies are milling about. Notice they have left a path just clear enough for the truck. (01:02:40)
Other mistake: The dead Killer Whale washed up by the lighthouse was visible from the teens AND in their line of sight while they sat on the shipwrecked boat, also their Catamarans they pulled onto the sand were literally 100 feet away - as seen in the wide shot, but yet it was a surprise when Tina and Eddie come upon it. There's no wrack line showing in the sand so the whale didn't "just wash up "
Other mistake: Fred MacMurray is listed as "Clarence" in the closing credits, but when he is standing outside his store and talking to Maureen, a promotional sign in the background spells his name as "Clarance."