Continuity mistake: At the end, when Jack shoots the main bad guy, he had already double-tapped somebody, but then shoots at least 5 more shots from a 6-shot revolver.
Continuity mistake: When Reggie asks the pickpocket at the bar to buy him a drink, you can see the bartender pouring his drink in front of him. The camera angle changes and the bartender is seen pouring his drink but she is standing much further back from Reggie.
Continuity mistake: Reggie's suit and white shirt never gets dirty, even though he was inside a bus which flipped over 17 times. No marks on his face or body, no blood stains or dirt on his white shirt and/or suit.
Factual error: No handgun shots can throw a police officer through the air halfway over a diner. That's just pure Hollywood fantasy (Mythbusters even proved this using all kinds of guns).
Continuity mistake: Cherry Ganz's tear drop tattoo on his left eye appears different from scene to scene. At the beginning of the movie, the tear drop tattoo is seen with two smaller drops on top of the large one. In other scenes, the two smaller ones are not visible at all, and he only has the one tear drop.