Factual errors: During the entire movie at specific points, the girl looks at a digital clock on the car. Yet we are also shown that there is no key in the car (which is why the car would not start), and in those cars digital clocks would not operate without a key in the transmission so the time could not have been showing at all times.
Continuity: There are three different license numbers on the BMW that the girl is trapped in.
Continuity: When Alvin is in the car with Mary Saunders - her bra is off in one shot and back on again in the next.