Continuity mistake: In an early part of the movie, Francis Tierney, Sr. is standing in front of a paper towel dispenser in a restroom with his son, Ray Tierney. The dispenser, which is visible over Francis Tierney's right shoulder, is at first full of paper towels, then empty, then full again. The paper towels are at first sticking out of the bottom of the dispenser, then they vanish.
Visible crew/equipment: Just before Colin Farrell shoots the guy in the bathtub, the shadows of the camera, some wires and a boom mike are visible.