Continuity mistake: When Veronica comes to Billy's house, she starts beating the crap out of him, and then pushes him into the pool. During that whole fight, she never even goes underwater, but her hair seems to be wet all over. After she starts getting through to Billy and talking to him, her hair is dry at the top. The only parts that are wet are her tips which are actually in the water. (00:05:50)
Continuity mistake: When Billy and the people who work at the mansion are playing kickball, after he runs to second base, the sign in the background says something about Billy's team always winning. But when the camera cuts to the 2 nurses on first base the sign is in mid-stroke of changing into something entirely different. And the camera change is too quick for it to have done that automatically.
Continuity mistake: During the singing number where Billy decides to go back to school, Billy, Veronica, the kids, and the clown are on the front lawn. Billy is standing on Veronica's left. However, in a wide shot when they start "Do you have any more gum?" Billy is on Veronica's right.