Revealing mistake: When "Roy" is punched in the water by Mr. Brady at the end, when "Roy" hits his head comes up and it is obviously not Tim Matheson.
Revealing mistake: In Hawaii, when Roy throws the little statue, you can see the thread which guides it to the spider.
Revealing mistake: In the scene where Marcia and Greg are building a house of cards to see who gets the attic, they keep breathing deeply and blowing air out. This reveals that the house of cards is obviously glued together.
