Gaffes

The Fiat car used by the Mechanic in the case in Naples area is blown up. However the car is used again a few minutes later. Not only is the registration plate the same, it still has only one brake light working.

At the end, when Steve takes the taxi to Arthur's house, it can be seen that Steve's car has no note attached to the rearview mirror. When Steve leaves Arthur's house and goes to his car, there is a note on the rearview mirror. This should have been visible from the taxi.

When Bishop is photographing the first victim's apartment from across the street, the bed is to the far left of the window; yet when Bishop is later reviewing the pictures he took back at his home, he looks at a picture of the bed and side table with a clock but from the position that the photograph had been taken, it could only have been taken inside the victim's room looking towards the window. This shot would've been impossible for Bishop to take from across the street.

When Steve pulls up to Bishop's house he pulls the car into spot facing in then in Italy Bishop is killed when Steve pulls up in taxi at Bishop's house the car is now facing out who moved it.

After the driver of the Chicken Lickin truck gets out, the door closes. In the next shot, Steve is seen closing the same door.

(at around 1 min) When Bishop is photographing using a telescope, the image should be upside down.

While the Questar telescope would produce an inverted image if an eyepiece were used, the penta-prism in the camera viewfinder reinverts the image to be right side up. The telescope functions as a telephoto lens and presents a normal inverted image to the film plane.

Arthur Bishop (Charles Bronson) tries to destroy the photos of his victims in his fireplace. That would be fine in a wood-burning fireplace but his is gas.

A gas flame will ignite a photograph as easily as a wood fire. The picture ashes would be more evident in a gas fireplace, but the photos would be incinerated the same.

When The Man is shown painting the leopard, there is no paint on his brush.

Boom is seen visibly at top of screen, when Bishop goes for his first heart check up.

Arthur has picked the door lock of the movie's first victim and prepared the bedsit for the hit. He leaves via the same (and only) door. As the door shuts behind him, the lock is visible and clearly is unlocked, which means it could not remain closed; it would either swing open or the hit would realize someone had been in his room.