Despite being absolutely drenched with blood during the zombie massacre, Lionel's sweater and pants are completely dry in all the following scenes. His pants are amazingly clean, too.
Lionel is mopping up bloody footprints when Paquita comes to visit. After they chase her dog upstairs and come back down, the entryway no longer has footprints.
When Lionel drags the baby out of the radio, it has no umbilical cord. In the next scene it hangs out of the baby, and it plays an important role when the baby is stopped by it.
Just after the Kung-Fu Priest scene, and Lionel is feeding the zombies tranquilized porridge, the nurse swallows some and it pours out of her throat. After Lionel has put it into the nurse's throat, the porridge has disappeared.
When Uncle Les first enters the house, he practically gags on the smell, but later in the party scene, no-one notices any unpleasant odors, even though the bodies have yet to be buried.
On the bottles, tranquilizer is spelled "tranquillizer". Merriam-Webster's online dictionary lists "tranquillizer" as an acceptable variant.
Incorrectly regarded as goof.
Telephone. When uncle Les uses the phone to report what happens in the house, the numbers in the rotary dial are in reverse order, number nine the first when normally number one is the first. This is for real, it's a thing exclusive to New Zealand and different than for the rest of the world.
When little Selwyn is chased by Uncle Les, the running baby is a stunt double who is clearly much larger than the baby is for the rest of the film.
On several short shots of the tramways, the carriages appear clearly as models pulled by strings.
When 3 of the zombies are high on Animal Stimulants and are going rabid at the house party, several girls have locked themselves in a room. A guy starts to crawl in with no flesh from his waist down. In one of the shots as they pull him in, you can see his real body as the skinless legs are kicking.
As the three zombies go rabid at the house party, and McGruder and Void tear the skin off a guy's face, the switch from actor to dummy is visible and is the most noticeable "actor-to-dummy" transition in the movie due to the dummy shot being slightly zoomed-in compared to the actor shot.
When the Thug Zombie has been torn in half and is crawling toward Lionel, you can see the shadow of the actor's body being dragged behind it.
The female police officer removes the fish hook from her thumb the long way out.
The lawn mower in the movie was not available in New Zealand in 1957.
Uncle Les' sports car is a 1961 MG A, four years out of date for the movie's 1957 setting.
A Coca-Cola sign, of a type that was not introduced until the 1970s, is visible in Paquita's family's store.
The display outside the fruit shop, where Paquita works, is partly stacked on green plastic apple crates. These were introduced in New Zealand in the mid 1970s. The film is set in 1957.
The first Aleister Crowley "Thoth" deck appeared in a monochrome edition published by the Simpson Printing Company of Dallas, Texas, in the early 1960s. Llewellyn, in conjunction with the Ordo Templi Orientis, published the first color version in 1969.
Lionel gets bitten by Selwyn twice, but doesn't get turned into a zombie.
When Uncle Les first enters the house, he practically gags on the smell, but later in the party scene, no-one notices any unpleasant odors, even though the bodies have yet to be buried.
Before the luncheon scene, the Mathesons introduce themselves to Lionel as if for the first time. At the funeral, they display long-term familiarity ("Poor Lionel, he was always dreadfully attached to his mother.")