The hair on the werewolf's face. Some tight shots on the eyes show nothing but hair, but other shots show the werewolf's dark skin with hair further away.
The light from the fireplace in the film's ending. When the power goes out the room is dark, despite a fireplace having been lit. After the werewolf makes his entry- the room is fully lit again with the fireplace.
On the new version of "Silver Bullet" when Marty is caught on the bridge out of Gas the fuel gauge shown on the dash of "Silver Bullet" is made by Sun Instruments. A few moments later after he is able to get "Silver Bullet" started and in fleeing from the Reverend down the road they show another shot of his Fuel Gauge indicating how low on fuel he is and this time the fuel gauge is a Stewart Warner.
Marty hands the screwdriver to uncle Red, but a few seconds later he suddenly has it back.
When Uncle Red is revealing the race car wheelchair to Marty, Marty's hair changes shape back and forth between shots.
A shopkeeper places a sign in his window announcing the availability of Remington shotguns in "single action" and "double action." Shotguns may be either single or double barrel, but they are never described as single or double action. Only revolvers and certain auto pistols are described in this way.
The newspaper date showed Friday, September 8, 1980. That date actually fell on a Monday.
At 25:05 the Newspaper date is 1980, while in the beginning narration it states that it's Spring 1976.
The narrator of the movie says that the full moon in 1976 fell on October 31. This is incorrect as the moon was just past half on October 31, 1976. She also states that the moon had not set yet and that it was already 3:00 AM. Moonset for October 31, 1976, was at 1:42 AM.
When Brady is flying his kite, a string can be seen above the kite holding it in place.
When Janie goes into the barber shop, the barber is holding the scissors about three inches away from his customer's head and only pretending to cut his hair. You can see the barber doing the exact same thing when seen cutting a customer's hair in the beginning of the movie, just after Arnie is killed.
When Gary Busey is protecting himself from the werewolf with a fire poker, the poker bends in half.
Marty is in the park flying kites with his friend Brady and is up on a tree limb getting a kite down. Janie helps him down from the tree limb and we see that the limb he is on is too high for him to reach from his chair.
When six of the vigilantes enter the fog-shrouded marsh, the first one killed is an African-American man in a red baseball cap, who is flung against a tree before being dragged beneath the fog. Yet, when Aspinal is killed next, and his decapitated head waved around in the werewolf's paw, like a trophy, moments later, the African-American vigilante is one of the survivors shown running off in panic.
In the scene where the boys are successfully flying kites, not a single twig is moving on any of the trees suggesting that there is no wind at all.
When Jane goes into Reverend Lowe's garage, among the large pile of empty soda containers are some Diet Coke cans. Diet Coke did not exist in 1976 (the year in which the movie is set).
When the townsmen are reading a newspaper, the date on the paper says 1980. The film takes place in 1976.
The film is set in 1976. In various parts of the film, you can see automobiles from the 1980s.
After Marty returns from shooting the werewolf in the eye and huddles against his bedroom wall, you can partially see a Reggie Jackson California Angels poster next to him. The film takes place in 1976, yet Jackson didn't join the Angels until 1982.
When Marty is in the tree with his kite, it is plainly seen that he has a calculator wristwatch. Although the film takes place in 1976, the calculator wristwatch was not invented until 1977.
When Arnie Westrum is killed at the beginning of the movie, the coroner concludes that he got drunk and fell asleep on the tracks; implying that a train took his head off. However, Arnie's track cart is parked only a few yards away on the same tracks that he supposedly died on and couldn't have died because of a train accident without causing a major accident. The cart, body, and tracks are all clearly visible.
Mr. Fairton was a witness to the massacre of the lynch mob in the swamp. He saw people being tossed around and ripped apart by something not human. He even saw the large, hairy claws ripping Mr. Aspinall's face apart. But still, people think it's an ordinary psycho killer when he can verify that it's not human. The only other time he's shown, he's acting calmly as if nothing ever happened. At the very least, he'd be scared enough to move or stay indoors.
When Jane is helping Marty out of the tree(as he was up there to retrieve his kite) one of his legs is moving back and forth. Corey Haim's character is supposed to be paralyzed from the waist down. That is a logical error.
In the scene right after Marty shoots the werewolf in the eye and rides back to his house, you can very obviously see his legs moving when he climbs from his window to his bed, even though he is supposed to be paralyzed from the waist down.