Continuity mistake: In the bus scene, when Stallone goes on the bus the number is 9372, when he kicks the bad guy out of the window the number on the bus' side is 9369.
Factual error: In the first few minutes, right before the explosion of the car with the little girl, Stallone is running like mad to disarm the bombs (on the pillars of the bridge). However, he isn't fast enough, and the last bomb explodes. The trick is that the bombs are just chunks of TNT, planted about eyeheight, but when the bomb explodes, the flames and stuff go upwards (not reaching/hurting Stallone, who is about 3 meters up and at the exact height of the last bomb).
Factual error: When Stallone first gets on the bus, not only does he not pay but he also brings a cat with him.
Continuity mistake: In the warehouse destruction scene, the exhaust fan from near the roof is blown out in an early explosion and lands on a police car. Later in the scene, as the warehouse continues to blow up, the fan is back in place on the building, spinning away.
Continuity mistake: In the love scene with Sharon and Sly, they stand beside the bed and Sharon puts her purse on the bed, when the camera changes shots and returns to the angle the purse is on the floor.
Continuity mistake: When the men go up to Stallone's hotel room, you can see them going down a long passage and passing a few rooms before coming to his door. But when the room blows up, the shot from outside the building shows nothing to the left or right of his room. What happened to the rest of the floor?