Deliberate mistake: In the last sprint towards the finish line, before they have to race on foot, the Lamborghini passes Fenderbaum and Blake. The red Ferrari they are supposed to be driving, is on the bed of a truck being towed. Notice the height difference between the two cars; about ten seconds later the two cars are pretty similar in height. (01:23:05)
Deliberate mistake: After Perseus and his men defeat the scorpions, Kalibos goes after him, lashing his whip. But curiously, the whipping leaves no visible marks.