After Shawn's first fight when he arrives at the night club he is seen stepping out of the car clearly sporting 2 bruises on his face. After the scene shifts to the interior, his bruises have all disappeared.
When Shawn crosses the street carrying a box full of umbrella's in the rain, he stumbles upon Harvey sitting inside the diner with his body facing towards him. As he approaches him the angle in which he was sitting changes and he is now sitting with his back facing Shawn.
Shawn MacArthur crossed the road under heavy rain with wet box, after he went and get back money from Harvey Boarden in minute back on street there was no water, no rain, box are fully dry in some shot even there is no any rainy environment.
In the scene where Harvey pays a visit to Jack's office in the back of the store. Harvey knocks on the door then proceeds to enter the room. In the next shot, one of Jack's men opens the door for Harvey and there is a wall and a clothes rack behind Harvey.
In the last fight of the film Shawn rams Evan into a wall, which caves in from the impact. When Evan pushes back, Shawn reaches out for something to grab and accidentally pulls down the "crumbled" section of wall (actually a thin sheet that had been placed over the real one), exposing it as a special effects prop.