Deliberate mistake: When Arthur is drawing letters of the alphabet, he only draws the outside of the letter A, not the horizontal stroke in the middle, yet it appears on the blackboard.
Deliberate mistake: In order to get to Julius Caesar and evade her nasty brother Ptolemy's assassins, Cleopatra concealed herself in a rug that she has a slave carry to Caesar. Look at the furled rug the slave carries on his shoulder. Then watch Cleopatra fall out as the slave tosses the rug to the floor and unfurls it. The slave would have needed wall-to-wall carpeting to hide her.
Deliberate mistake: Mitch carries Annie's body into her house through the front door, which he doesn't close behind him. In the next shot as he leaves the house it's been closed and he has to open it before he walks out. (01:32:20)