When the candles in the cathedral spontaneously ignite, the puddle of wax at the base of the wick shows that each candle has been burning for longer than they appear to have been burning on screen.
When Maggie O'Connor returns to Cody's room after the rat dream, she has no scratches until after she puts Cody down.
In the scene with the homeless man, Eric Stark recites a spell in Hebrew that is later referred to as a "Druid Rune Spell from the 16th century."
Druids did not cast black magic spells, and lived around the 10th century.
A man pours gasoline all over himself and lights a match. He holds the lit match inches in front of him, yet it does not ignite the gasoline.
Maggie's car explodes in mid-air while falling from a bridge. However, it had clearly already caught fire.
As Maggie and Cody are driving to Vermont it is supposed to be the day before Easter Sunday (March or April) and yet mid-autumn foliage can been seen outside.
When Maggie enters Cody's room after the rat dream sequence, she completely misses the light switch yet the lights turn on.
There's an AWARD BIOS SETUP screen visible on the computer that the FBI detective turns off. There's no reason for him to be there and he shouldn't even be able to get to it on a NYPD network.
During scene when Maggie is at the front desk of a New York police station, a form with the word "Ontario" and its provincial emblem at the top appear in a brief close-up of the desk.
Maggie and Cody run past a Shopper's Drug Mart on the street after leaving the dentist office. Shopper's Drug Mart in a pharmacy chain located only in Canada, and yet the scene is set in New York City.
During the scene in Eric Stark's New York apartment, the Skydome (located in Toronto) can be seen in the window.