When Maggie drops Lucas off for the first time, he leans the seat forward to collect his bike from the back seat and closes the door without putting the seat back up. When Maggie grabs his net and umbrella, the seat is still down. When the camera shifts to the other side of the car, the seat is up again.
Lucas talks about locusts in the film. The insect featured in the movie is a cicada.
Not all cicadas reproduce in 13-17 year cycles. One species found in the US has a brood emerging every summer, and spends 2-5 years underground.
There are a lot of things wrong with the football scene at the end of the film. The most egregious is that when Lucas fails to catch the forward pass, that's an incomplete pass (and a dead ball) not a fumble.
When Lucas picks up Maggie for the dance and arrives at the door, his hair is nicely parted. After the clip of her mother, the view returns to Lucas and his hair is back to being tousled.