In the second baseball scene, Joe is sitting on the bench next to one character with the number 8 and Simon, who is on Joe's other side is also number 8. Two players on the same team would not be the same number.
In the scene where both boys are in the school, just before breaking in Father's office, the dog is licking Simon's glasses, this leaves a wet smeared mark. In the next shot, the glasses are clear again.
In the Christmas Pageant scenes, Miss Leavey is seen pulling down on the rope that raises or lowers the kid playing the angel. By pulling down on the rope, the kid should go higher. But when Miss Leavey pulls down on the rope, the kid is lowered as well.
When Rebecca Wenteworth is walking towards the baseball diamond, she is looking behind her and waving. When she gets hit in the head with the ball, it's on the wrong side of the face. She should have been hit on the left side of the face.
As the bus heads down the hill towards the lake we see Simon with his glasses on - then there is a close-up of him without his glasses, then as the bus hits the water he's wearing them again and they fly off and hit the floor.