Revealing mistake: After Spirit gets his second wind when the Colonel is attempting to break him, he breaks the girth/cinch strap by catching it on the fence. At one brief point, the pole of the fence actually appears to pass between Spirit and the girth of the saddle.
Revealing mistake: When the head of security carries Arnold and Gerald into Scheck's office, as the camera zooms in on Scheck, one of his buttons disappears twice in two frames, and his other button completely disappears mid-shot. (00:30:18)