Revealing mistake: When the shark bursts through the window of the cabin, in each of the shots facing Brody, including when he shoves the air tank into the shark's mouth, the glistening water is visible in the window's reflection behind Brody. The shark's reflection is never seen behind Brody, despite the shark's massive size in the small cabin. Bruce must have had the day off during Roy Scheider's takes. (01:58:00)
Revealing mistake: During the chase sequence towards the end of the film, Roger shoots five bullets into the windscreen of the blue car. If you look carefully, you can see there is no driver in the front seat.
Revealing mistake: Walter and Joanne have two little girls at the beginning of the film, but then much later, there are suddenly two young boys seated at the table during breakfast. (01:17:00)
Revealing mistake: Segment 2: After the doctor pulls off her wig and long after any residual movement from that action should be possible, the "dead" Therese moves her head slightly on the pillow. (00:43:50)