Continuity mistake: When Spartan and Huxley arrive at the cryogenics place to battle Phoenix and what remains of his gang, Phoenix sees them on the monitor walking into the building and you see Spartan on the left and Huxley on the right. The camera angle changes to an inside view and Spartan is now on the right.
Continuity mistake: When Spartan and Phoenix are fighting in the sewers, Edgar Friendly shoots his gun at Phoenix and you see the catwalk that Phoenix was on tip to its side and Phoenix dropping down to the ground with the plank of the catwalk right below him. When Phoenix lands on the ground the plank is nowhere to be seen. It should have been right below him.
Continuity mistake: When John Spartan is frozen in the cryochamber, at the beginning of the movie, if you watch during the credits - while the time is going by the small circular monitor that is on his chest, it changes from the left side to the right side of his chest in almost every shot.
Continuity mistake: When Phoenix first gets out he makes his way to a computer and the police come to arrest him. Phoenix takes one of the policeman and pushes his head through the side glass pane and walks away to fight the other officers, but when Phoenix goes back over to the computer the glass is not broken.
Continuity mistake: In the opening credits when Spartan is frozen, both hands are up either side of his head. In the very next shot his left hand is by his head, but his right arm is out stretched and in a down position, impossible as he is frozen. Also his mind altering sensors are on the left side of his head and body before freezing, next shot they are on the right side of his body.
Continuity mistake: When the Cryo-Prison worker opens the cabinet that holds the cylinders that contain the blue "freezing balls" to freeze Spartan's slush, the slot on the center left is empty. When the shot changes to the worker pulling the cylinder out, the slot to the lower left is now the empty one.