Officer Harrison fires 14 rounds out of a six-shot revolver.
In the middle of the film there is a scene where immense amount of blood squirts on the windshield of the van. Marion uses the windshield wiper to get rid off it but on the next scenes one can see a totally clean windshield again.
Early on in the film when Rene is sat in the Volvo and a zombie is under the car she is wearing boots. However when she climbs onto the roof of the car she is only wearing socks until the zombie knocks her off the roof and she lands on the ground, at which point her boots have returned.
When the party enters the General Store, Marion walks in completely naked. In the next shot, inside the store, we can clearly see him wearing striped boxers.