Visible crew/equipment: There is a shot towards the end of the film, (just before Willis and Jackson exchange dialogue in the engine room) in which it shows the entourage of people boarding a smaller boat from the much larger ship. Look towards the bottom left corner of the screen as the boat pulls away - inside you can see the head of a female boom mike operator.
Continuity mistake: Towards the end, when Bruce Willis notices the writing on the aspirin bottle, he leaves it in the phone booth and the camera jumps towards it a couple of times. In the first shot the writing's almost vertical, but in the following shots it's at a definite angle. (01:48:35)
Visible crew/equipment: When Zeus and John get the cab after being attacked by the group of dudes in Harlem, as they are riding to the police station you can see the camera truck out the back window of the cab.
Suggested correction: How do you know that's a camera truck? Could be just any regular truck passing by.
There is a camera held out of the passenger side window of the van.
Visible crew/equipment: When Simon and Katya are in the helicopter, both are replaced by obvious stunts. Simon has dyed blond hair as opposed to his brunette stunt, while she has short and straight hair, but her stunt's is long and curly.
Revealing mistake: When Simon is in the helicopter and shoots at McClane, check the metal strips next to his feet and the protruding metal parts where the squibs have been placed to allow for the pyrotechnics.
Continuity mistake: When the cab drives between the two trucks it comes out without a scratch. When it crosses the park it is damaged all over.
Continuity mistake: Before the cab drives through Central Park McClane slams on the brakes. Skid marks from previous takes can be seen on the pavement.
Continuity mistake: After exiting the aqueduct, McClane falls in a puddle, hair slick, soaking wet and covered in mud. Zeus calls him and McClane turns around. In a brief shot from behind him his hair swaps to clean and fluffy.