When Dexter goes to the abandoned church, it is nighttime but the stained glass windows have steady light behind them. There is no electricity and no daylight.
While Dexter is talking to Travis at the museum, another man walks into the room. Dexter tries to hide his face by putting his left hand over the right side of his face. However, when the camera angle changes, Dexter has his right hand covering his face.
When Gellar hurts Travis with the searing rod, Travis's screams can be heard a solid second or two before he physically reacts in the next cut-scene.
Professor Gellar says that the Devil has tempted people with an apple. The Bible doesn't say the fruit of the tree of knowledge is an apple, or any other specific fruit. Someone who is supposed to know the Bible well wouldn't make that mistake.