Continuity mistake: After Benedict is introduced, Frank's head swaps from turned to the left, next to the target, to centered, several centimeters away.
Continuity mistake: After Arnie electrocutes the baddie, Benedict aims a knife at him, and Danny pulls him away. Benedict's stunt double is noticeable because he is plumper, and his hairstyle differs.
Continuity mistake: When the thugs crash against the cardboard boxes, the stuntman flies face down horizontally, yet a frame later he is flying upwards, as if ejected.
Continuity mistake: Jack shoots at the elevator glass ceiling, but a frame later the remaining pieces have changed.
Continuity mistake: When Benedict pulls the corpse's finger, his watch is right next to the suit's sleeve. A frame later there's a 5 centimeter gap in between both.
Continuity mistake: Arnie tells Jack Slater, "Call my office," then there's a side angle of Arnie, and it is very obvious that it's not him but a stunt double.
Continuity mistake: During the shootout the baddie lying dead on the couch has his head turned to the left. A frame later it's facing the right side.
Continuity mistake: In the alleyway, the thugs' truck crashes against the boxes sideways, from a 7 O'clock position; yet a frame later it is crashing from a 9 O'clock position.
Continuity mistake: When Danny enters the theater for the preview, the wetness of his hair changes back and forth.
Continuity mistake: When Danny suddenly appears inside Arnie's car, between the chase and explosions until they park the car, none of Danny's movements and positions match between the close-ups and the wide angles.
Revealing mistake: After Slater jumps out of the house and it explodes, when the cop car flips over, the air ram used to flip it over is visible.
Audio problem: When Daniel and Jack are driving around looking for where the "bad guys" are you can hear their voices echoing when they are still sitting in the car indicating that it was rerecorded. (00:40:50)
Chosen answer: The kid points them out in the film, in order to convince Arnold's character that he inhabits movieland. Also, after Arnold's character falls into the tar pit he is able to completely wipe himself clean, an obvious intentional continuity error.