I thought at least some of the OBVIOUS mistakes....
Like when the 3 girls are walking after school and Linda makes the comment,"Speed kills!'
Following the stop and the Shape driving off again, they HEAD THE OPPOSITE DIRECTION they were going:heading once again toward the school.
Another one I thought was funny, was when Donalds character is on the side of the road on the pay phone.....when he goes and discovers the truck, you can clearly see the boom operator in the pay phone reflection
All in all....I enjoyed it immensely .