Revealing mistake: When Uncle Mike and Johnny go upstairs at the party to hustle Phil and company, Phil shoots the eight ball towards the corner pocket, and the sound effect indicates he made the shot. Phil says, "That's how we do it," but right as he says this, the eight ball is seen slowly rolling back into the shot, revealing he actually missed the shot.
Continuity mistake: At the end of the movie when the main character takes his stack of money and wraps it in his light jacket. As he walks with it in hand he leaves the building while talking to his opponent. Upon exiting the building in the next shot, he's wearing the jacket and there is no sign of where the large stack of money went.
Continuity mistake: When Johnny is congratulated for his victory by Danny and his friends outside, there's a scene where they push him around and it alternates between a normal shot and a closeup to Johnny's face. It's very easy to spot that the closeup is definitely another separate shot because the expression on his face changes from one to another pretty obvious.