Revealing mistake: During the final chase, Jaclyn Smith's double stuntwoman is extremely evident. (00:43:45)
Revealing mistake: After Max the dog breaks free from the cage and then bites through Callahan's chains, the two head to the metal barred window and Max begins pulling on one of the bars with his teeth. Which are obviously rubber, as they 'bend' slightly as the dog is pulling.
Revealing mistake: The set where Augustus visits Agrippa on Lesbos for reconciliation is the same set where Augustus already was before - he was there earlier, reading the news of Marcellus' death while he was away from Rome to visit the Eastern provinces. But as stated, he had not visited Lesbos at all, because he and Agrippa had temporarily fallen out. (00:39:30 - 00:41:30)
Revealing mistake: In the arcade the killer talks to his helper while playing a pinball machine. He plays very agitated and strongly. But if you look closer at the below end of the playfield you see that there is no ball and the flippers aren't moving. (00:23:50 - 00:24:48)