Continuity: When the drug tester gets done with testing the heroin, he blows out the lit candle on the bottom. But when there is a far shot of him talking, the candle is still burning.

Continuity: During the car chase scene under the "B" Elevated Train in Brooklyn (86th St.), Gene Hackman passes the same curve at least 3 or 4 times. Look closely, you'll probably see the same movie theatre over and over again. Apparently, they rerun the same chase clip to increase the length of this scene.