Walk Hard: The Dewey Cox Story (2007)

Revealing mistake: When Dewey is singing the protest song about midgets in 1966, modern cars can be seen driving in the background.

Factual error: Young Dewey is seen driving a tractor near the beginning of the movie. The year is supposed to be 1946, but the tractor is a 1950's Ford.

Revealing mistake: When the black singer of the band of the nightclub can't perform, Dewey steps up to prove his worth. When he starts getting really into it, he joins the piano player in playing some tunes. You can see some keys playing, but they are not being touched by either person. (00:20:50)

Knever

Dewey Cox: Edith, I am starting to think... that maybe you don't believe in me.
Edith: I do believe in you. I just know you're gonna fail.

Pa Cox: You're not half the boy Nate was. You're not even half the boy that the top half of Nate was after you cut him in half.
Dewey - Age 8: So you're saying I'm less than a quarter of the boy Nate was?

Nate: Dewey, I'm cut in half pretty bad.