Continuity mistake: During the car chase the damages on the car differ in every angle. The copilot door's glass, for example, swaps from being slightly broken, to totally shattered, then perfect, then it's gone, then it's slightly damaged.
Continuity mistake: The main character portrayed by Bruce Willis walks out of the elevator with his jacket buttoned up, but crooked. (It's buttoned up wrongly.) In the next shot it's back to its proper self again.
Continuity mistake: When Willis's surrogate is lying on the ground with a woman pointing a rifle at him, the collar on his shirt swaps from being away from the face to up and very close, between the wide and close-up angles.
Continuity mistake: At the end of the movie Willis arrives home looking for his wife. There's a close-up of a yellow bottle surrounded with pills. Its position and the amount of pills changes in the wide angle.