(at around 1h 18 mins) At the end, when the two country guys are at the cellar door, one is using a chainsaw to cut through the door. The film shows him cutting through the 2x4 on the inside of the door even though the hole in door shows he should have clearly cut through it already.
The blood smudge on Barbara's cheek changes shape several times.
In one scene, it shows 3 zombies abreast moving toward the camera. Two of them are moving in the typical zombie manner - slowly and mechanically. The third zombie (on the right) is moving much faster than the others. The scene cuts briefly to another scene then it cuts back to the 3 zombies. The one on the right is now moving much slower like the others. When the camera first cut from that scene, the director undoubtedly chastised the third actor zombie and told him to slow down before doing another take.
When Barbara enters the farmhouse, it is daytime. She sees blood dripping from the ceiling. Hours later, when it is dark, Ben starts to go upstairs and Barbara alerts him to the dripping blood. The blood would have coagulated by that time, so it wouldn't be dripping.
Barbara is seen on several occasions firing many shots from her rifle while gripping the barrel with her left hand. In reality, after just a few shots the barrel would become far too hot to handle in this manner.
After being attacked in the cemetery, Barbara runs past a hearse next to an empty coffin. She gets into her car, then sees a man in a suit walking towards the car. She calls to him for help, and then his clothes - which are slit up the back - begin to slide off his body. Clearly, this ghoul is the body that was to be buried that day - he climbed out of the coffin and everybody scattered. That being the case, his clothes should have fallen off long before Barbara saw him.
(at around 58 mins) In the scene preceding the venture to the gas pump, Ben creates a makeshift torch out of a table leg. He continues to shake a can of lighter fluid over the rag, implying that he is dousing the rag in fluid, but when he does so, the spout of the can is not open. No fluid would be able to pass through.
(at around 5 mins) Obvious dummy when Johnny is killed at the beginning of the movie.
Both in scenes where Barbara is loading the rifle, and where she's wearing the policeman's gun belt across her chest, anytime the head stamp of the bullet is shown you can see that the primer pocket is empty, meaning the rounds are dummies.
When the zombies are eating the remains of some people outside the house, one of them picks up a hand which is obviously made of rubber.
When Ben and Barbara are visiting the cemetery to say hello to mother they run into their first Zombie. In the scrum that proceeds the zombies first lunge at Barbara, Ben tries to protect his little sister and is apparently bitten. When looked at closely however you will notice that the zombie's teeth never come very close to making contact with Ben's arm or even his tweed jacket yet he belts out a scream as if he's in pain from the zombie's dental damage.
When Barbara is beating uncle Rege with the poker his eyes are closed, but when she puts the rug over him to cover him up his eyes are open.
(at around 12 mins) After Ben shoves a body out the kitchen door, you can see a cameraman's reflection in the door window.
Barbara and Johnny only experience strange occurrences after they arrive at the cemetery. However, when Barbara arrives at the farmhouse just a few minutes later, five people have been hiding in the basement for some time. Barbara and Johnny should have seen/heard about the weird happenings before they ever got to the cemetery.
When Barbara is loading the Henry lever action rifle, she is loading the cartridges bullet first. This would lead to a malfunction in the rifle, as the bullet end must be facing toward the muzzle for the cartridges to properly feed from the magazine tube into the chamber.