Continuity mistake: When Larry is burning his books he throws one at Dorothy who is looking out of the window. The upper right part of a window pane breaks, but in the next shot the left side is broken. (00:11:20)
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.
Revealing mistake: During the beginning, as the newspaper headlines roll, the small text in the articles is actually the same text repeating itself over and over again, something like: "an investigation issued."
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)
Plot hole: Spoiler Warning. It turns out that Dan Merrick is actually Jack Stanton after a whole lot of reconstructive surgery to make him look like Dan Merrick. Everything is believable except that he has Dan Merrick's voice as well. He should have Jack Stanton's voice.
Revealing mistake: When the assistant warden explodes after his body starts inflating due to the warden shooting him with the elephant bullets, in the close-up shot of his head exploding, we can see that his head has been replaced with a fake dummy head. (01:23:18)
Other mistake: Despite Lena's cab driver and his wife both being Armenian, the wife's speaking Spanish.
Character mistake: Cynthia Kellogg comes forward to voluntarily give information about the James Urbanski case. Detective Nealy tells Kellogg, "As a matter of procedure, I have to inform you of your rights." Kellogg says she didn't do anything so doesn't need a lawyer. Nealy replies, "This is your right" and proceeds to inform her of her Miranda Rights. Miranda warnings are applicable to suspects/defendants who are in police custody (under arrest) and about to be interrogated, not voluntary witnesses. (00:03:02 - 00:03:57)
Character mistake: In the very first scene, in the first shot you see a sign in Spanish that says "NO PASE por orden del departamento de arquiologia". The correct Spanish word is arqueologia.