When Mason calls Becker to tell him about the footage that he caught on camera, before Becker is told to pick up the phone by Max Quentero, after Max speaks, you can hear Jack Axel say, "Becker, pick up on Line 3." even though his mouth is not moving.
At the beginning of the movie, right after the doctor tells Capt. Hulland that Storm is dead, O'Malley turns around and, after Hulland tells him he's sorry, in the audio you hear him say, "The most unstoppable sonuvabitch I ever knew." But if you watch his lips, he says "The most unstoppable sonuvabitch I ever met."
When Storm is holding the Senator towards the end, the Senator calls the police officer walking up to Storm "Sergeant". The officer has Captain's bars on his uniform, Sergeants wear chevrons on their sleeves.
When escaping the ambush at the hideout, Mason drives the black jeep across a field (and crashes through a white pavilion) and one shot is flipped - you can see the bullet holes in the windscreen move around, and Mason at the wheel sitting on the wrong side of the car.
When Storm fights the four guys in the billiard room he stabs Jack Axel in the jugular with a pool cue, he then falls to the floor and dies with the cue still lodged in him. When Hulland enters the room shortly after and sees them laying on the floor either dead or unconscious, the cue that was lodged in Axel has vanished.
When Mason finally confronts senator Trent, he leads him to the main room, where he threatens to shoot Trent in the mid section. The gun fires, and from the reaction, Storm fires into the ground. Yet a later wide shot reveals that there is no hole in the floor, and the tiles are perfectly intact.
After climbing the mountain at the hideout, Mason Storm sits and watches the sunset which is alternately behind him and to his left (over his left shoulder), and in front of him and to the right between shots.
As she sits down to her desk, Andy says "It's 6AM. Morning Martha." The scene immediately cuts to Andy back up from her desk continuing to speak while walking toward Martha. During the whole walk the wall clock behind Martha's seat shows 5:50.
The fireplace poker near the end of the movie loses its top after one swing, then reappears in the next cut as the bad guy charges Storm. Additionally, the poker starts out with a brushed or dull finish when first seen, then when Trent tries to attack Mason with it, it's brightly polished.
After the fight scene at the friend's home, you see Mason driving the Jeep through the field/grass. In one shot he is driving with Andy is in the passenger seat, yet in a shot right before they hit the wooden archway it's possible to see a man on your left (the passenger seat) and a blonde woman n the right. Clearly neither are 'Steven Segal' or Kelly LeBrock.
When the Jeep driven by Mason Storm hits the bad guy in the field, the bad guy flies straight up into the air. The laws of physics dictate that he would fly away from the Jeep in the same direction as the Jeep is traveling, if not simply get run over.
After a firefight in which he fires two shots from a pistol holding at least seven, Storm racks the slide on the pistol, presumably to cock it before the next firefight, but this would be unnecessary as the next round in the magazine would already be loaded, and cocking it from this position would simply eject the next round. No round is ejected, and the pistol is revealed to be empty, as a round would be visible through the bullet ejection hole if there was one in the gun.
During the gunfight in the house Det. Sgt. Goodhart's rifle jams. In the next scene Mason shoots Det. Sgt. Goodhart. The person being shot is pictured in full frame in the following scene and is obviously the stunt double and not the actor portraying Det. Sgt. Goodhart.
During the ambush at the hideout, there is a henchman at the front door, when Mason throws Andy to the floor, and covers her up just before the explosion of the door, you can see that the man who is protecting her is a stunt double - his face is turned towards the camera.