Continuity mistake: When Jim and Jack are in the morgue, and Jack says, "Is there anything else you like to comment on?" the doctor is standing next to Jim writing something down on a pad or piece of paper (you can see the pencil), but in the following shot he is not writing on anything and his hands are behind his back.
Continuity mistake: Close to the end of the movie when Jack Cole is riding in the car with the two Russian mafia guys, one of the guys says "Coldest winter I can remember in L.A., the wettest too." The guy puts his hand up to adjust the rear view mirror, and then puts his hand down; in the following shot, you can see he puts his hand down again.
Visible crew/equipment: At the end of the film, when Cole saves Campbell from falling, they then proceed to swing down the rope, and if you look closely, you can see a crewmember's arm sticking out of a window holding a piece of equipment attached to the rope, making sure that they don't swing out too much.
Deliberate mistake: Just before Donald has a fight with Jack at the end of the film, we see Donald jogging down a flight of stairs to escape the building. Then after a bit of a punch up with Jack, we see Donald running back up the same staircase to escape Jack, but when he reaches the top it turns into a dead end. There is nowhere that Donald could have came from when we see him coming down the stairs.
Continuity mistake: At the end of the film we see Jack have a fight with Donald. Then Jack says " If thats the best you've got, I'm just going to have to kill you". Then Jack grabs Donald around the neck with both hands, but when the camera changes to behind Donald, Jacks hands are not around Donald's neck.