Revealing mistake: During the initial breakout of the Gladiatorial training school an armed guard is stabbed on a balcony and falls to the arena below. He gets up and walks into the doorway adjacent to where he had fallen, apparently satisfied that his part was completed.
Revealing mistake: During the slave revolt at the Gladiator training academy there is a wideshot of the arena (with the slaves/soldiers fighting in the background) where you can see a slave trying to climb up a banner to the podium above. A soldier reaches down and stabs the slave however you can see he doesn't actually stab him. The slave then drops down and does a death twirl which isn't very convincing either. (00:56:42)