Revealing mistake: In the scene where Doc Brown is following Biff into the tunnel, as Marty starts to pass between the cars on his hoverboard, one of the wheels on the rig supporting the hovering DeLorean is visible. (01:30:30)
Visible crew/equipment: After Indy and Henry have escaped from Castle Brunwald, Indy jumps into one of the boats, pulls the motor starter cord and jumps back out, then just as he bends over to release the boat from the piling, right between Indy's legs the black covered arm of a hidden crewmember appears from under the tarp taking hold of the throttle, steering the boat away from the pier. (01:02:40)
Continuity mistake: When Nick is in the spoon, the milk around him turns green.
Visible crew/equipment: During Bud and Coffey's fight in the lab, we see a lightbulb swinging from side to side between the two men. If you look closely, you can see a hand (belonging to a third person) pushing the lightbulb. The only people in the room are Bud and Coffey. (01:44:16)
Visible crew/equipment: After Bond received a lighter from Felix and Della, he uses it, and the flame is big. In the beginning and the end, you can see a tube is connected to the lighter, and the tube goes into his suit. (00:15:00)
Continuity mistake: While Dana is cleaning her baby for the bath, the bottle and sponge next to him move around between shots, the tissue popping out appears/disappears randomly, as does a towel on the corner. (00:45:20)
Continuity mistake: When Wallace races to get crackers, check the packet's logo. When the camera angle changes it's different. (00:08:57)
Continuity mistake: When Fuller falls to his death, the mannequin used as his stand-in gets decapitated on its way down. It even makes a loud noise. When Fuller lands, however, his head is still on his shoulders.
Continuity mistake: During the classroom scene, the spelling of of Genghis Khan's name on the chalkboard changes from "Genghis Khan" to "Ghenghis Khan" between shots. (00:04:50)