The bomb is supposed to go off exactly at sunrise (which it does), but the stock shots of the fire trucks rushing to the scene after the explosion are in pitch blackness.
The clock ticking down the final minute before the bomb goes off is out of sync with the dialog.
The handwritten note from the ABM bomber is different between shots. In the closeup it has five lines but in the medium shot it has six lines.
It's stated that Code 10-13 is for Officer needs assistance. But a 10-13 is used to report Weather conditions.
When Marty Foreman makes his first effort to sprint his brother Hoyt from police custody, he consults a wall directory which gives the number of Chief Clifford's office and, below that, the number of Broadhurst's office. Broadhurst never had an office; he always worked at a squad room desk.
Clifford is a captain and should have at least four lieutenants working for him, maybe more. None are listed on the wall directory Marty Foreman consults.
The bomb devastates the squad room ceiling (and, apparently, the man beneath it), but the furniture in the room is almost completely untouched.
The shot of McCloud when the Doctor is thanking him was printed backwards.
The bomber pulls the bomb out of his tool bag in the middle of the crowded squad room to install it and nobody notices what he's doing.
Police headquarters is being evacuated when Parks and Marty Foreman bring Broadhurst into the building in a last-ditch effort to look for Marty's brother. Somehow they find an unguarded door and can move throughout the building (which is still being evacuated) and nobody notices.
The policeman who gives Norton the note from the ABM failed to tell Norton to handle the note carefully. She couldn't have known it was evidence unless the policeman told her.
McCloud's scheme to arrest all of the drug dealers to find the one who was selling to the woman would have produced numerous lawsuits. The police can't just arrest people because they're looking for someone.