Revealing mistake: During the first battle the Romans had with the Germans, they show a scene in slow motion with very emotive music that shows the massacre in the forest. Look closely at all the Romans and you will see one fall to the ground, then, as if it was a rewind, come back up again - and then fall again.
Revealing mistake: At the end, when Maximus had gone to afterlife world of Elysium and was meeting his wife and son, both the wife and the son put their hands up as to shield the sun from their eyes. You can clearly see that their hands are not blocking out the sun, because the shadows are not over the eyes. (02:19:45)
Continuity mistake: During the battle of Carthage, Hagen stands alone with an arrow in his shield, couple of scenes on, no arrow, couple of scenes on again, an arrow hits his shield. (01:21:20)
Continuity mistake: When Maximus has escaped being executed in the forest, he throws a sword into a soldier. Slow it down, the sword is actually already there in one shot, then it appears suddenly. Also the sword penetrates the left side of the body near the heart, yet when we see the soldier falling from the horse it's in the middle, then back to the left side. (00:39:00)The-Immortal
Continuity mistake: After Juba has thrown the sword to Maximus, Maximus tries to gather the gladiators by shouting "Single column, single column," then it cuts to him charging on his horse while holding his sword arm out. When it cuts from behind him he is holding his sword arm in front of him instead. (01:24:10)Mortug
Continuity mistake: When Hagen is shot in his leg with an arrow he is holding the arrow in his leg. Maximus notices the chariot charging for Hagen and he shouts "Hagen". It cuts to Maximus running against Hagen, but now we can see that there is no arrow in Hagen's foot. When it cuts to Maximus reaching Hagen and pushing him away from the chariot the arrow is back in his leg. (01:22:45)Mortug
Continuity mistake: At the end of the battle with Tigris of Gaul, Maximus kills the tiger that leaps on top of him and throws it off to the side. In the next shot the tiger is back on top of him and he has to fight with it laying on his stomach. Later the tiger is once again off to the side. (01:42:15)