As Paul is running along in the diving gear towards the queen, he passed a police officer firing at spider from behind his squad car. You can hear the officer firing 3 shots. His gun however, clicks back empty after seeing 1 shot.
Military HMMWVs don't have HUMMER emblazoned across the back of the tailgate.
When Roy (the father of Paul and Petra) has died, you can clearly see the actor breathe because of the coldness.
When the family is driving in the parking garage, you can see the whole camera team in the rear view mirror of the car.
When the spiders first appear and the characters rush back onto the bus, Tracy Gold rushes up and jumps into the front seat, her mike pack can be seen on her back.