Continuity mistake: When Pete and Elliott return to their hideout after the ordeal on the truck is over, it is dark. Moments later when Bryce Dallas Howard arrives, there is a lot more light coming in through the trees and the scene looks brighter. This is in the space of five minutes or less.
Factual error: When Pete is riding on the back of the school bus and jumping on top of the bus in the background a New Zealand style Give Way sign is seen and also on the left hand side of the road. The film is set in the USA so this should have been on the right hand side of the road.