Continuity mistake: Early in the movie, when Jill St. Claire tip-toes into the house while Jimmy the Tulip is busy with household chores, she invariably gets caught by the new family man anyway and eventually takes the argument with him upstairs to the bedroom. Carrying on the shouting match with her husband while getting change in front of the closet, a pair of shiny silver handcuffs (most likely the kinky kind - what business could a hitman possibly have with handcuffs?) can be seen hanging behind her head. By the time the outer layer of her clothing is stripped, the handcuffs disappear.
Continuity mistake: The first time Bruce Willis talks to Matthew Perry on the phone Bruce holds the phone in his right hand. Bruce's watch changes positions, well below that bump/bone below the wrist to above the bump/bone and then below again. Bruce never lowers his arm, or the phone, to cause the watch to move.