Deliberate mistake: There is one scene in the movie where Heath Ledger reads a Latin sentence in a book. As he is translating the sentence, he goes over the words one by one with his finger. This would never be possible in a Latin sentence, because words in Latin are never in exactly the same order as in English. Words that actually belong together can be placed at opposite ends of a sentence.
Deliberate mistake: When Kate Barlow shoots the Sheriff, she shoots him between the eyes, but when she kisses him there is no hole or anything on his face.
Deliberate mistake: When Leota is in the front seat of the automobile, the air bag is still full. Air bags will deploy and then immediately deflate to prevent people (or women in crystal balls) from being trapped. (01:10:45)
Deliberate mistake: After Emily talks to inspector Girotti she starts a record player. Then she walks over to the window, sees Werner in the garden, and decides to go down. Between shots she appears behind him, which is wrong, as the song from the record goes on, but it's most probably intended. (00:30:45)