Continuity mistake: When Greg and Pam are dancing in the restaurant, just before De Niro picks up the message from the neighbour about the cat, when the shot is on Greg's face their heads are together, but when the shot is on Pam's face, their heads are separated. This is shown like 8 times, 4 times each side.
Continuity mistake: In a few scenes of Pam's bedroom, if you were standing at the foot of her bed and look to the right you would notice that there isn't a night stand nor a lamp sitting on it. So how is it that Greg happens to turn on a lamp that is sitting on a night stand when he proposes to her?
Continuity mistake: In the 'race scene' near the end of the film, just before Greg and Jack go their separate ways, you see Larry (who is sitting next to Greg) say, 'Oh, look, there's Jack. Hey, Jackie,' and he waves. Then it cuts to Jack, who is looking at Greg, and then it goes back to Greg, and in the background you see Larry and he is unfolding a newspaper and starts reading it. Then it goes back to Jack, and then back to Greg, where you see Larry with his hands on the dashboard, looking at Jack. So what was with the newspaper? Where did it come from? How did it disappear so quickly?
Continuity mistake: When Pam goes into the den to console Greg after firing the 'shot heard round the world,' she puts her arms around his neck. In alternating shots, her hands go from under the hood of his sweatshirt to on top of the hood.
Continuity mistake: During the scene when everyone is gathered around discussing the whereabouts of Mr. Jinx, Jack announces "We'll just have to reschedule..." Debbie jumps up from the couch and when she does she hits the coffee table causing one of the edges of the table to fall and hit Denny's knee. The next shot the edge is back in place off Denny's knee and Denny has slightly changed positions.
Continuity mistake: Before and throughout the scene where Jack demonstrates his hidden cameras, the lemon and cherry in Greg's glass keep moving around.
Continuity mistake: When Greg is trying to open the suitcase, the top pouch is empty, when the delivery man drops it off, and when Jack tries to open it, the top pouch is full.
Continuity mistake: In the beginning of the film, when De Niro is holding the cat explaining to Pam and Greg how he taught the cat to use the bathroom, the cat changes from shot to shot. In some shots it's a very fluffy Himalayan with a lot of black on its head, then the next shot it's a much less fluffy cat with more gray on its head. The positioning of the cat in De Niro's arms also changes from shot to shot in this scene.