Continuity mistake: During the big fight scene near the end, the baddie manages to drop the hero down an elevator shaft in a warehouse. The scene ends with a shot looking up the shaft at the bad guy laughing demonically, looking pretty mucky and with hair all over the place. Cut to the next scene where the bad guy appears in a room where the shield beam is generated. Now he is completely clean, has a different hairstyle, and if I remember right has a completely different costume on. (This is because the final fight is actually a combination of two separate scenes - the scene in the elevator shaft was originally meant to come halfway into the film, but the scenes around it were cut, so it was added into the final battle. It has been restored to its original place in the "Renegade" cut of the film, but this mistake is still present in the theatrical version).
Factual error: In the scene where Earl is fighting the other prisoner, he is using a "sword" made from a bar of metal, it has a blade that is well over 2 feet long from the tip to the hilt. At the end of the fight the other prisoner is standing with his back against a solid concrete pillar, but Blake somehow manages to shove the "sword" through him all the way up to the hilt. This wouldn't be possible unless Blake were somehow able to shove the bar into the concrete.
Revealing mistake: When Rollie is hanging from the ladder and the bolt breaks, you can see the smoke from the exploding bolt. (00:42:50)
Continuity mistake: Towards the end of the movie two of the mob goons are dangling Patrick Dempsey over the rooftop. After a brief scuffle Dempsey is hanging on by one of the men's pants, which are ripped down to his ankles. When it shows the pantless goon fall off it cuts to inside where the mob boss sees him through the window, but his pants are now pulled up.
Visible crew/equipment: When Frank and Tracy are about to surrender at the hotel and the cops start shooting, Frank yells "What the hell is going on here?" Frank then hides behind the car and you briefly can see the boom mike reflected in the car window. (00:52:20)
Other mistake: When Joe Huff goes to the fight pit and jumps in, he has on fingerless gloves. However, during the fight he is barehanded and when the shot returns to Joe Huff he has the gloves on again.
Continuity mistake: During the catapult launch for the SAM suppression mission, we can see two Shrike missiles on the right wing pylons. In the next shot, there is only one. At this point they still haven't reached the SAM site so they wouldn't need to fire one. A little later in another shot (right before they switch to active radar) we see two Shrikes again.
Other mistake: When the paperboy throws a newspaper at Hulk Hogan, and he throws it back, hits him and he falls off his bike into a bush. If you look closely, you can see him run into the bush, instead of being knocked into it.
Revealing mistake: At the beginning of the film when a Judge is thrown out of the airplane, you can see a parachute is attached to him.
Visible crew/equipment: When the cop car chasing the tow truck does a complete flip in the air, a roll bar is clearly seen where there was none before.
Revealing mistake: When Ricky punches the prison wall, the wall can be seen beginning to break apart a second before Ricky's fist hits it. (01:29:59)
Other mistake: The sword champion is murdered in a dark room. Cut to Tarek Richards by his corpse. The room is still shrouded in darkness, which makes for a cool transition. However, when the camera pans out and someone (with an audible click) turns on the lights, you realise that the room is full of cops which up to that moment have been working in a dark room for no reason - and they have been doing things that require reading and writing, like collecting witness statements.