Errors in geography: This film was obviously filmed in NYC but many scenes particularly the race scene was in San Francisco, others in Los Angeles, and there are plenty of California plate shots.
Continuity: As Jack enters the trading floor he takes a stack of trading slips from Chip's hands. A few moments later, his hands are empty and Chip hands him some trading slips again.
Continuity: During the final chase, Jack's face alternates back and forth from grimy and sweaty to clean between shots.
Continuity: During the bike race Jack's bike toggles back and forth between a one-speed-no-brake track bike and a typical multi-speed street/road bike.
Continuity: When Jack is twirling his bike's handlebars and wheel in his apartment the down-tubes on the front forks are straight, but the on his street bike the down-tubes have a slight forward bend at the axle.
Revealing mistakes: The very first time we see Jack on his bike is a reversed shot. The text on the sign Grand, Olive St and Trans Am on the car are all backwards.
Errors in geography: When Jack hits the Taxi and falls the license plate on the Taxi clearly says California.
Continuity: Jacks hair is noticeably shorter from the time he leaves Hector at the Hospital, to finding Terri on his doorstep.
Continuity: Jack hair changes during the final scene when he meets Terry on the street. It changes from long to short several times.