Continuity mistake: When the football players are trying to chase Lucas off of the field, Lucas is not wearing or carrying his helmet, and it isn't seen anywhere near him. When the players give up and decide to continue playing with Lucas on the field, in the closeup Lucas is putting on his helmet, which has magically appeared.
Continuity mistake: During the football game, after Lucas drops the football, there is a scramble to recover the ball. As Lucas turns to face the opponent who picks up the ball, we see #87 pick up the ball. The scene moves to the cheerleaders clapping, then when the scene goes back to the field, we now see that #44 of the opposing team has the football.