Plot hole: Shortly after the robbery, Kevin Kline and Jamie Lee Curtis get together in a little flat and Kline calls the police from a landline to tell them who committed the robbery. In England this would immediately lead the police to the flat from which the call was made, and the person reporting the robbery would be the first person the police would want to find and speak to. Otto has handed it to them on a plate. (00:12:29)
Plot hole: At the end of the film Mardukas reveals that he has been wearing a body belt packed with cash - "in the neighbourhood of three hundred thousand dollars" - ever since Jack detained him in New York. Are we to assume that Jack Walsh, an experienced, hard-bitten ex-police officer, now a bounty hunter who routinely chases down violent and armed bail absconders who would kill him without a second thought, didn't even perform a perfunctory search of Mardukas when he detained him? This man used to work for the Mafia! What if he was carrying a weapon? A body belt with three hundred one thousand dollar bills in it would be uncovered by even the most casual pat down.
Revealing mistake: In the final scene as Doc tell Billy good-bye if you look up to the top right hand corner of the screen you can clearly see a jet trail in the blue sky. Certainly not possible in those days. (01:42:20)
Continuity mistake: When the bad guys are outside the hotel in the convertible, they spot Lassard and one of them spits milkshake over the inside of the windshield. The milkshake disappears in the next shot.
Continuity mistake: You can see the flash of light that signals them to react to the bomb going off.
Character mistake: Watson says that there are fifteen windows on the front of 221B Baker Street, but if you look, there are only twelve.
Continuity mistake: When Freddy and Janet arrive at Lawrence's mansion as his house guests, they arrive at night. Lawrence takes them upstairs and asks Janet to waltz with him in his ballroom. The scene takes place only a few minutes after their arrival. As they begin to dance, Freddy crawls to the door and starts moaning. Lawrence then shuts the ballroom door in his face and resumes dancing with Janet. As the shot cuts back to them dancing, a large window is plainly in view and daylight is streaming in brightly through the sheer curtains.
Other mistake: As the murderer spots a police car coming towards him he turns to his right onto a dirt road, there is a huge boulder at the point where he turns, marked "No trespassing, Bishop Falls camping". As he turns he sideswipes it, rocking the boulder, however the sideswipe has no effect on his vehicle.springbok
Visible crew/equipment: In the radio control car chase scenes over the humpy streets, camera equipment is visible in the rear seat area of the lead car.