Continuity mistake: During the match, when funny music is playing, the guards attack the Mean Machine team. Monk has left empty the area (this is not the part when they do the goal), and you can see that there's nobody in the Monk's area. Change of shot, and suddenly there's a person of the Mean Machine team. Change of shot (when the ball almost enters) and there's nobody again in the area.
Continuity mistake: During Monk's demonstration, he grabs the hairs under Billy's right armpit, but Billy rubs the left side in the next shot.
Continuity mistake: When Ketch and Chiv grab Danny in the showers, Danny fights back and Chiv drops his knife on the ground. Just as the guards walk in, Danny drops his towel to cover the knife, but throughout the rest of the scene, the towel that was dropped on the floor is nowhere to be seen until the guards turn to leave, then it reappears.