Continuity mistake: As Arnie runs after Leigh at the drive-in, he arrives under the awning with his hair slightly wet, but still rather full-looking. But in the next close-up, it's soaked flat onto his head. (00:45:40)
Continuity mistake: After shutting his closet door, Tad runs over to his lightswitch. In this shot the lamp on the desk, beside the lightswitch, is standing high up. In the next closeup of Tad reaching the switch, the lamp is in a different position, then switches back. (00:04:25)
Visible crew/equipment: After Calvin Bouchard makes the announcement to tourists visiting the Undersea Kingdom to evacuate, we see the tour guide lead the crowd through the tunnels. The green screen backdrop is still in the final cut. They forgot to add in the underwater effect.