Revealing mistake: When Bluto is watching the sorority girls have their pillow fight and he falls down with the ladder, you can see him land on a grass mat that is cut into the lawn. It's funny because you can see the grass push in. (00:40:00)
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: In the scene during the American bandstand, at the end of the song when the teacher is dancing in front of the band members, the crews can be seen. The dressing and the hair doesn't match Grease era at all, and someone is sitting on a director's chair as well. (01:06:20)
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: Near the beginning when Lois and Clark are walking out of the Daily Planet, Clark gets stuck in the revolving doors. But, look closely at the glass door, and you can see Richard Donner (confirmed in Superman expanded commentary) holding the door so that Christopher Reeve can get stuck.
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)
Revealing mistake: During the final chase between the son of the Sheik and the evil oil company henchman, Tomas Milian is replaced on the speedboat by a stuntman wearing a bad wig in some shots, and in other shots by the cutest little puppet that rides the cutest little toy boat. (01:23:00)
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)
Visible crew/equipment: Near the start, after the chopper crashes in the field, while Jack Riley is talking to Von Schauer and George Wilson we can see the small microphone clipped to Jack's shirt under his tie. (00:05:40)