Revealing mistake: In the scene on Christmas morning when the Bumpus' dogs run in and eat the turkey, during the shot of the dad sitting in the chair reading the comics, one of the dogs bumps the camera and jostles it a little bit.
Revealing mistake: During the last Race (the Agua Caliente), Phar Lap's hoof was re-opening from a crack earlier in the movie. When they show the close up of the leg/hoof during the race in slow motion, the "blood stain" keeps moving around on the leg wrap and hoof area.