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)
Continuity mistake: In the scene where Jill distracts the contract killer nude, her hand with a gun changes position between the shots. (01:06:00)
Audio problem: When Oz lies in the dentist's chair he has a mouthpiece (connected with anesthetic) lying on his forehead. When he gets up the mouthpiece falls off his head with a great "POP" sound effect. This sound would only occur if there were a vacuum, which there wasn't. (00:46:15)
Audio problem: As Yanni is getting off the plane there is the sound of the plane's engines slowing to a stop but the engine is not turning at all. (00:59:30)
Deliberate mistake: Jimmy catches a fly in the air and puts it in his mouth. He then spits it out with great power. You then hear a "Bzzzzz." assuredly made by the fly. How can a fly flap its wings when spit out in that velocity? (00:48:30)
Continuity mistake: When Oz realises that Jimmy "The Tulip" Tudeski is his neighbour, we see a few newspapers flying up on the screen, on the second newspaper the article with the title "His "Two Lips" are Sealed", the article text does not match the headline. (00:08:25)
Continuity mistake: When Nick and Jill are eating at the outdoor cafe the bottle of Pepsi turns around from shot to shot. When the camera focuses on Nick, you can read the whole word "Pepsi" but when it's on Jill you can still read half of the same word even though she's on the complete opposite side of the table. (00:06:10)
Continuity mistake: When Oz is at Gogolak's house you can see a bottle of vodka on Gogolak's table. When Oz leaves the bottle is gone and now there is a jar of water on the table that wasn't there earlier. (00:26:05 - 00:26:55)
Factual error: When Sophie hires another contract killer, they are having sex at Niagara Falls. It seems that a few hours later they have driven to Montreal, which is almost 7 hours away. The movie implies a very short distance between Niagara Falls and Montreal.
Visible crew/equipment: Near the end at the fine art museum, the camera moves in for a close up of Oz in the Beatle. When it does, you can make out the camera in the Beatle's paintwork. (01:20:20)
Other mistake: When they've duct taped the cop to the x-ray machine to check the outcome of the procedures Oz did on his teeth, there is no film in his mouth as the machine takes the x-ray. (01:17:20)
Continuity mistake: As Jimmy & Oz drive from Oz's house to the city, the background behind Oz's side of the car changes from a new suburb in a wooded area (with a degree of unfinished construction) to a large, long-completed residential valley, and back again. (00:11:30)
Continuity mistake: When Cynthia and Jill discuss the money in the bank they are both in the visible shot. In the next shot Cynthia is gone. (01:28:50)
Continuity mistake: When Oz and Jimmy are talking on the Royal Mount, there's a florist stall, with a panel written "fleuristerie". Some shots later, it is bigger with "floreteria" or something like that written on it. (00:13:05)
Continuity mistake: After Cynthia tells Jill she loves Oz in the bank, we see a long shot of the boat and Jimmy has his hand to his ear, looking like he's holding a phone. We then hear a phone ring, cut to a closeup of Jimmy with his hands by his side, and he lifts the phone to speak. (01:30:15)
Continuity mistake: When Oz and Frankie gets in to the hotel room where Jimmy is waiting for them, Oz bumps into Frankie and knocks over a lamp. He gets up holding the lamp in front of him. The way he holds it changes during the shots, and the lamp shade changes position. (00:39:55)
Continuity mistake: When Oz is telling Jimmy about his father in law's loan you can see a man standing beside him turning his head to the left. When it cuts to a closeup the man is looking forward. (00:13:25)
