300 (2006)

Revealing mistake: In the first major battle between the 300 Spartans and the Persians, Leonidas is slaughtering the Persians and the speed of the scene goes from slow motion to fast motion, you see very realistic CGI blood. When the blood hits the the ground it suddenly disappears. This happens many times during this long and awesome scene.

Revealing mistake: After Leonidas pushes the Persian messenger down the rather large hole he turns around to walk away. In that shot (when he is walking away) you can see that the scar on the top left corner of his chest is only a prosthetic, because it has come unglued and is lifted up.

Revealing mistake: When the baby is being "inspected" in the beginning, it is pretty obvious that in some of the wideshots that it is just a dummy and not the real baby.

Revealing mistake: Leonidas gets cut over his eye during his battle with the Uber Immortal. During several close-ups of Leonidas after the battle you can easily see that the "cut" below his eye is nothing more than a red line. Doesn't look anything like a cut or scratch.

Nick Bylsma

Revealing mistake: Several of the characters in the film have vaccine scars on their upper left arms. Queen Gorgo and Daxos are the readily apparent ones.

Revealing mistake: In any close up of the God-King, particularly in the first meeting with Leonidas, it is obvious that all his piercings aren't real. There is flesh-coloured adhesive joining the rings to his face.

Revealing mistake: When a Spartan is climbing down from the walls, he steps on a Persian body, and his foot sinks right into the corpse, showing that this "body" is a stuffed dummy. (The body is not boneless, drained of blood, or crushed by the Spartan's foot. It's a mannequin.)