When the movie opens and the two barrels containing dead bodies fall out of the cargo trucks there are no military vehicles following the cargo trucks to maintain the transfer.
When Ed first looks at the corpse he's going to behead, the hair is matted, dirty, and covered in cobwebs. When he lifts the head to put it in the bag, the hair is loose and clean.
Ed hits Doc Mandel with the bedpan on the right side of the head, but Doc puts his hand to the left side, and later has a band-aid on the left side of his head.
When Doc's car drives through the garage door and into the Zombies, a large crack is made in the windshield. The windshield is undamaged in all subsequent shots.
When Brenda, Johnny and Ed get out of the car to go into the building in the cemetery, the right front door of the van is open. In the next shot, the door is closed.
The Zombie shot in half had lost his hand in the car window in the previous scene. When he lifts his torso by his hands to attack the gang in the hospital cellar, his hand reappears for one shot. In the commentary, however, the director mentions that this actor was one of several used for multiple scenes. His description suggests that this wasn't supposed to be the same zombie from earlier.
(at around 9 mins) When Jesse falls through the coffin in the mausoleum, it is clearly a stunt double. Jesse has blond hair, while the double has dark brown.
(at around 44 mins) During the "Severed Hand" sequence, person's arm attached to hand-prop visible.
When Joey steps out of the van at the cemetery he is wearing a pair of Converse shoes but when he leaves the mausoleum he is now wearing Addias.
Just before the severed hand scene, when the car roof zombie is still fighting with Ed, you can clearly see the actor hasn't makeup in his neck, revealing his true skin tone.
(at around 1h 6 mins) In the church, when Brenda says, "Okay, take them baby," her mouth does not move. It also does not move when she screams immediately after.
When the zombies are being electrocuted, the shot of the last zombie standing alone in the back there is a crew member watching on.
(at around 17 mins) When the army is examining the barrels of corpses, two personnel are in full anti-contamination suits complete with masks & breathing apparatus. Less than 3 feet away are various soldiers, sans protection, who don't seem concerned.