Continuity mistake: The Bismarck is sighted by a British agent in southern Norway, sailing out of the Baltic into the North Sea - east to west. But the view through the agent's binoculars shows the ship sailing from right to left on the screen - which would be sailing west to east from the point of view of an observer on the Norwegian coast.
Continuity mistake: In an early scene Travis and Dickenson are in Travis's office. Travis goes to the mantel, gets a cigar and pours himself a glass of sherry. In a later scene, when Travis meets Crockett in the cantina he refuses a drink from Crockett claiming he doesn't drink, ever.
Continuity mistake: Just before Crassus has Spartacus crucified, he tells him the fate of his wife and son. A camera close-up shows a change in Kirk Douglas' hairstyle.