Krushinski is just demoted from starting quarterback. He mentions to Molly that he makes a great slot back. The next scene is of a slot back making a great run, only the slot back is black. He gets tackled and when he gets up you see a very white Krushinski with the ball.
When Finch threw Coach Darwell in the mud at the end of the championship game, the coach lands on his back and then rolls around, but his face and the front of his jacket are already covered in mud before he rolls over.
When Molly returns home and goes to put ice onto her bruised face, her children are watching television in the living room. The eldest daughter has maroon hair in this shot, but this is well before she dyes it that color later in the film.
When coach McGrath is taking the Jackson High School mascot, a goat, back to Jackson High School, although she is alone in the van, you clearly see a hand holding onto the goat's leg so he doesn't move around.