Continuity mistake: When the devil is falling apart and his 2nd ear falls off, he tells Nicky he cannot hear him, and asks the demon by his side who catches it to put it back on his head. But towards the end, when the devil is reduced to no more than a mouth and 2 arms, he is able to have a conversation with his demons about what's going on and hear them perfectly.
Continuity mistake: Durring the second encounter with the blind man, after Nicky and Valerie bought their ice cream, watch as the blind man runs into the light pole and in the backround Nicky and Valerie are turning the corner. In the next shot Valerie and Nickie are turning the corner that they have supposedly already turned.
Continuity mistake: When the devil starts deteriorating, the first thing to fall off of him is his pinky finger. Later, when the devil is deteriorated down to two arms and a mouth, he has two thumbs and eight fingers.
Audio problem: When the demon pulls the devil's pinky off a demon says "gross" but his mouth never moves.
Visible crew/equipment: In the church scene, when the priest stops dancing on the pizza and the camera goes up you can see in the left middle of the screen a camera just poking out as when the priest talks it goes right to him.