Continuity mistake: When the real 'manager' comes outside to yell at "Mr. O'Donnell', you see the manager walk back into the club. If you look in the background of the next shot, you can see the manager walking through the door again. (00:13:25)
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. (00:52:05 - 00:58:50)
Continuity mistake: In one of the opening scenes when Bob comes in from walking the dog in the rain, he dries the dog off with a towel and puts the towel on top of the coat tree. He tries to feed the dog and when it cuts back to the dog the towel is on the floor, then his wife comes in and the towel is back on the coat tree.
Continuity mistake: When Elliot's the basketball player, when he scores the slam-dunk and breaks the headboard, he breaks the headboard after the slam as he bounces/hangs off the headboard. But in the replay he breaks the headboard as he makes the slam and then bounces/hangs off the headboard. (00:49:10)
Continuity mistake: Ben Affleck has a large tattoo on his right shoulder/bicep that has been covered up by make-up for the movie. During the 'waterpark' scene Ben is wearing a T-shirt and when he scoops the little boy out of the water and lifts him into the air the sleeve of his shirt pulls back a little and you can clearly see the bottom of his armband tattoo.
Continuity mistake: When Mel tries on the pantyhose, the hole in the left leg changes from large on the outside of his leg, to small with a run on the outside of his leg to large on the inside of his leg. (00:25:45)
Factual error: When John Cusack puts Springsteen on his LP-player, he places the needle at the start of the record. The song that plays is the studio version of "The River." Therefore, the album has to be "The River," which is a double album, but "The River" is not at the start of either of the two LPs, but is the last song on LP #1. (00:18:10)
Continuity mistake: When Paul goes to get pizza and a movie for Dora, the movie messes up the order that he gets them. First, he goes to the pizza place, and picks up a pizza, you can clearly see him holding a bag. Then, he goes to the video store (with a cameo by David Spade), he has nothing in his hands. Then, he has both after.
Continuity mistake: It's pretty interesting that Charlotte is supposed to be suffering from a terrible heart condition, yet whenever she's in the hospital, there's never a heart monitor anywhere around.