Revealing mistake: When the couple in the truck are driven off and down the side of the mountain the direction of the truck does not match the direction he steers the truck.
Revealing mistake: At the end, the bodies falling off of the fire engine ladder are obviously dummies.
Revealing mistake: The blue Willys (Jeep) station wagon used for the blue-screen shots was a two wheel drive version. During the argument shortly before the crash, the Englishman driver abruptly shifts gears, revealing the three-on-the-tree shifter on the steering column, used only on 2WD versions. The on-location filming used the 4WD version, with the logos visible on the tailgate and side of the hood. Also, the distinct 4WD front axle can be seen in many shots.
Revealing mistake: Whenever a back projected shot is used the cars are supposedly driving at top speeds yet no-ones hair, hat, scarf etc ruffles in the wind. In fact there's no evidence of movement whatsoever. This is particularly noticeable in the scene where they are all crammed in the truck and one guy is leaning over the side shouting at drivers.
Revealing mistake: At the end when Culpepper slides down the cable on the palm tree branch, you can see the actual rigging inside the palm tree branch that is used to slide down the cable.
Revealing mistake: Watch the firetruck ladder as it sways. During the long shots showing the entire ladder, it is swaying from ground level. During close-ups, the apparent pivot point is just off the bottom of the screen, indicating a much shorter ladder was in use.
Revealing mistake: At the end when the police officer crashes through the window of the pet store and all the dogs are licking him, it is extremely obvious that it is short piece of footage being rewound and played over and over again to extend the length of the shot.
Revealing mistake: Sylvester is shown in his car chasing after Finch and Hawthorne in their rental car to try to get them to stop. There are about five shots during this sequence that show the two cars side-by-side in the foreground of shot. In these shots, it is apparent that the cars are positioned on a fake background and not actually driving. This is especially noticeable as they are shown driving on a bumpy road, but during these specific shots, the cars appear completely still, with no signs of vibrating or bumping up and down. (01:51:53)
Revealing mistake: After getting out of the river, Meyer hitches a ride with a random driver who stops for him. There is a shot of the car beginning to drive off, and after they have driven off, a helicopter emerges from the field in the background to follow them. Just after the car exits the shot, and just before the helicopter emerges from the field, a visible edit can be seen onscreen revealing that these were two separate shots edited together. (01:45:45)
Revealing mistake: At the beginning of the movie when the car goes through the guardrails and is falling down the mountain side, at first the car is seen coming down sideways, driver side facing down. Then it mysteriously changed to be right side up in the next shot when it crashes.
Revealing mistake: During the whole movie any time someone is driving, the driver turns either way too much or not enough for the turn they are on. Even when they are driving straight, they turn the wheel as if they are going back and forth on the road in both lanes.
Revealing mistake: In the chase scene, Milton Berle and Terry Thomas are actually driving two different blue '61 Chevrolets. Initially, they are in a rare Super Sport as evidenced by the crossed flags emblem on the rear seat speaker cover. Fortunately, the car they eventually crashed was the less desireable non-SS version (i.e. no crossed flags emblem present). (01:40:05 - 01:47:25)
Revealing mistake: When Mrs. Marcus falls after slipping on the banana peel, two wires used to help pull her backwards can be seen. (02:40:12)
Revealing mistake: When Mrs. Marcus walks into the hospital room to shout at the men, she is shown slipping after stepping on a banana peel. A closer look will show that she reacts to slipping on the banana peel and begins to fall backwards a split-second before she actually steps on it. (02:40:12)
Revealing mistake: When the cab driver lands on the statue of Abraham Lincoln, the right hand of the statue can be seen wobbling, revealing that it is a rubber prop. (02:36:38)
Revealing mistake: During the chase scene where the two taxicabs are chasing after Culpeper, the chase is shown going into a street. There is a shot shown from behind the three vehicles where they drive around a broken down car parked in the middle of the street. A man can be seen climbing onto the back of the car and can then be seen momentarily looking at the camera, presumably to avoid coming into contact with the car that is filming the chase scene. (02:27:57)
Revealing mistake: When Sylvester is chasing Finch and Hawthorne and the two cars bump into each other, there is a shot of Finch and Hawthorne's car swerving off the road and then back onto the road. In the shot, it can be noticed that Sylvester has been replaced with a stunt driver. (01:51:57)
Revealing mistake: When the fireworks explode in the basement, there is a shot of Melville running up to and jumping over a counter to take cover. In the shot, we can see that he has been replaced with a stunt double. (01:38:30)
Revealing mistake: When Melville is shown driving the crane across the basement floor, actor Sid Caesar has been replaced with a very noticeable stunt double. (01:17:55)
Revealing mistake: In the garage fight scene, the two mechanics are shown attempting to flee by rolling underneath the garage door and Pike following them the same way. The camera then holds on the garage door before the two mechanics are thrown through it. Just before the mechanics go through the door, there is a visible shift in the appearance of the door revealing that this supposed one single shot is actually two separate shots spliced together. (00:55:34)