Continuity mistake: At the beginning, the undercover cop says the combination is 666. But the lock has a 4 digit combination.
Factual error: When Stowe and Callaghan shoot each other at the end, the CGI shell casings have huge, unrealistic primers.
Continuity mistake: When Stowe walks into the police station for the first time after waking up, he is wearing a necklace. The next shot shows he isn't.
Factual error: In the restaurant shootout, the man shoots at Stowe with a 12 gauge shotgun from just a few feet away. When the projectiles hit the wall, there are only four or five and have approximately a 6 inch spread. Even an open choke shotgun with a short barrel would have a 2-3" spread at most at that range.
Factual error: When the older cop is in the trench at the end and his pistol runs empty, the slide doesn't lock to the rear as a Beretta should.
Factual error: During the big shootout at the end, Stowe picks up a Beretta semi-automatic gun after killing the owner, who is trying to reload it. Stowe inserts a magazine, sends the slide forward, and then racks the slide. A complete round should have ejected but did not.