Continuity mistake: When Mathew Perry goes to Chicago to meet with the head Boss, Bruce Willis' wife comes to talk with him at the hotel. In the scene where he is brushing his teeth he picks up the mouthwash bottle and swigs some, then sets the bottle down on the counter. The camera cuts back to her, then back to Matthew Perry, and the mouthwash is gone. (00:32:50)
Continuity mistake: When Bruce Willis first comes into contact with Michael Clark Duncan - in the hotel room MCD takes his sunglasses off but when he gives BW a hug they are on but when he steps back they are off again. (00:41:40)
Continuity mistake: When Oz is back from Chicago, after taking Jill to meet Jimmy, Oz calls Jimmy's wife, and when the phone rings, a red light shines on the phone. Then on the 2nd call the light doesn't shine anymore. (00:54:05 - 00:55:00)
Continuity mistake: When Cynthia goes to the bank to claim the $10 million, her hairstyle with the two barrettes keeps changing throughout the scene. (01:27:10)
Continuity mistake: When Matthew Perry is drinking with Willis' wife in the Chicago hotel room, the level in her glass changes - one minute there's not much in there, then it's half full, and then she swigs back the last drop! (00:33:50)
Continuity mistake: In the scene where Cynthia agrees to marry Oz, you can see her hair change position in between the shots. (01:30:45)
Continuity mistake: When Nick is having lunch with Jill (the assistant) the waitress takes his menu twice. Once while the camera is on Nick and once while the camera is on the waitress. The hand she's holding the menu in also changes from left to right. (00:06:05)
Continuity mistake: When Oz gets to the dentist's office the undercover cop lies dead in the chair facing straight left. In the next shot his head has turned. (01:12:25)
Continuity mistake: When Oz's wife is having sex with her new contract killer you see his necklace. Its position changes between the shots. (00:55:50)
Continuity mistake: During the boat scene towards the end of the movie, depending on who is talking (Jimmy or Oz), the sun is out when one of them is being filmed, then it is cloudy when the other one is filmed. This happens throughout the entire scene. (01:28:10)
Continuity mistake: The undercover cop got hit at least five times in the chest in the shootout scene, yet there is not a single drop of blood on his white shirt when his body is laid down on the dentist chair. (01:08:55)
Continuity mistake: When Matthew Perry is talking to Bruce Willis after their drive and he's sitting on the ledge, when he says "no, I live here with my wife" his hands are either side of him on the ledge or together in his lap, depending on the angle. (00:13:50)
Continuity mistake: When Matthew Perry is having lunch with his assistant near the start, when his meal comes his glass of water switches sides of the table depending on the angle. (00:07:10)
Continuity mistake: Jimmy's necklace change from being under his shirt to being on top of it between shots. (01:25:20)
Continuity mistake: When the bad guys get to Jimmy's house one of them tries to open the door wearing black gloves. In the next shot you see him trying to pick the door with white doctor gloves. Why did he change? (01:03:10)
Continuity mistake: At Jimmy's house Jimmy is having a martini. He empties the glass and puts it on the table. Then in two shots later he empties it again. (00:54:00)
Continuity mistake: When the undercover cop finds the tape recorder in the car he uses a white handkerchief in his left hand. In the next shot suddenly a handkerchief in his right hand appears. (01:17:55)
Continuity mistake: Sometime during Matthew Perry and Bruce Willis's first meeting outside Bruce's house, Perry tells him how familiar his face is. During one of the questions, the shades Bruce hung on his shirt disappear in one shot and reappear in the next. (00:08:55)
Continuity mistake: When Oz gets to Jimmy's house, you see Jill holding a gun at chest level and Jimmy pointing a gun her direction. When it cuts, Jill holds the gun at shoulder level and Jimmy's gun is lowered. (00:53:30)
Continuity mistake: During the shootout in the house, one of the gangsters falls down the stairs damaging the handrails with his head. A few minutes later, when Frankie is bringing the dead undercover cop inside, the stairs are shown in the background. The damage to the stairs doesn't match the previous scene. (01:07:10 - 01:09:35)