Revealing mistake: There's one bit where we see the shark slamming into a boat and gliding along the side with its mouth open. Not only does the shark's latex mouth bend beneath the snout, narrowing from pressure, but within the mouth you can clearly see yellow hydraulic tanks to open the mouth. (01:22:05)
Visible crew/equipment: Just before Laurie stabs Michael with the knitting needle you can see that one of the window shutters is open and that the wind is ruffling the curtain. When the camera gets closer and the curtain is out of the way you can see the huge fan in the studio being used to simulate the wind outside. (01:19:50)
Factual error: When they are refuelling the helicopter (as a zombie approaches quietly from behind) the actor has put the gas nozzle not into the hole for the gas tank, but into one of the foot-holes that helicopter mechanics use to climb up to the top of the helicopter to do repairs. It doesn't even fit properly. (00:22:55)
Visible crew/equipment: After Matthew and Elizabeth take the pills to stay awake, when they are found Matthew shouts, "David, don't let them touch her," and there's a visible T-mark taped to the floor in the overhead shot. (01:31:30)
Visible crew/equipment: You can see a crewmember in the woods, when Jennifer throws the huge log at the guys, during the big chase scene. (00:05:20)
Continuity mistake: The editing of the ski jumping competition is a disaster movie in itself: first we see #35 jumping and wearing a helmet while wearing a red and blue suit. Then comes #6, who starts to ski wearing a helmet and a marine blue suit, but when he jumps it's skier #35 again but now his helmet is gone. Now comes a new skier, #26, wearing a dark blue suit. When he picks up speed he is suddenly no-helmet #35 and -drumroll - when he jumps he's now yet a new skier, #27.
Visible crew/equipment: In the scene near the start of the movie when Lois Chiles is showing Mia Farrow her bathroom and Mia Farrow is saying "Yes, It's lovely," on the mirror on the right you can see a member of the crew crawling around on his hands and knees. This is visible on the DVD as well as at the cinema. (00:05:50)
Continuity mistake: During the first meeting between Lou and Madeline Kahn, her fur stole changes position between shots almost more often than she changes names. (00:09:30 - 00:10:30)