There were at least four slip-ups I could spot in the Battle of Carthage (1st big fight in the arena in Rome).
1> When the German is pushed to the ground to avoid the chariot blade, there's no way he and maximus could make it in time between camera angles
2> When the fit bird gets chopped in half by the chariot blade, the camera angle switches from rear to front. Look real carefully (maybe run it slowly) and I reckon her legs start spurting before the blade gets there (rear view). Cool shot though!
3> When the chariot smacks into the wall below Caesar, it puts on a burst of speed between camera angles
4> This one is well obvious! After Crowe decapitates the two archers, and while he does his marching about, there's a shot where his sword is really shiny and clean, while before and after it's bloody. No freeze-frame needed for that.
This was a really cool movie - but I wonder why they didn't see the last one?