Revealing mistake: When Batman brings the Penguin to the Batcave the Batmobile skids to a stop on the gray floor. It then begins to rotate in the next shot and it's now on a black platform. When the Penguin emerges from the car and walks toward the rear of it, the platform is obviously gone. (01:06:10)
Continuity mistake: When Lucy awakens at 4:00 AM she checks on Linus and then puts him to bed. In some shots there's a window over Linus' bed, but in other shots the window has vanished, and there's only a shelf over the bed. (00:23:10)
Continuity mistake: When Don Knotts is in the old Simmons mansion, he falls down a chute of some kind. If you watch closely you will see the stunt person looks nothing like Don Knotts. It is a younger man with very straight hair.