Goofs

When the gas station attendant begins to pump gas in the Karmann Ghia, none of the numbers on the gas pump move.

Towards the end of the movie, when the professor comes looking for his friend at the brothers' house, Frank has a shotgun in his hands as the professor pulls up to the house, but he leaves it by the door instead of just shooting the professor.

When Sue is first shut in the brothers' basement with the two other hostages, she asks "Who's this person they call Mama?" but she should have said "she calls" , referring to Stevie, since she's the only one, to that point, who'd ever mentioned Mama.