Continuity mistake: When Billy discovers Barney the dog wrapped up and hanging by the Christmas lights, Barney's face is pointed towards the house, but when the shot changes to Billy helping Barney down, the dog's face is turned away from the house.
Other mistake: Stripe manages to get the TVs and video camera working in the department store even though Kate hadn't turned the power on yet.
Visible crew/equipment: Before Billy's mum pushes the gremlin into the microwave, you can see the top of a crew member's head, on the left of the gremlin, next to the microwave.
Continuity mistake: When Mrs. Deagle is killed by the gremlins, throughout the scene she appears to be either bare legged or wearing beige-colored tights. However, when her corpse is on the ground after being launched out of the house, suddenly she's wearing dark blue tights.
Factual error: Gizmo could not drive the Barbie car because it's controlled by remote control.
Continuity mistake: One of the mutated Gremlins scratches Billy's hand and then grabs an apple. On the desk there is a fake brain. In between shots it goes from being on its side to sitting flat.
Other mistake: In the bar, one Gremlin is changing the music selection on the radio. However, the tuning knob is on the right side, out of his reach, the tuner doesn't move, but the music style changes.
Plot hole: The whole film is basically told as a flashback from Rand Peltzer's point of view. Now he might be able to talk about things that Billy, his mom, or Kate might have told him, but he wouldn't have known about all the other the gremlins did to the rest of the town like killing Mrs. Deagle, the cops, or the gremlin in the mailbox.
Other mistake: When the gremlin is using live wires to manipulate the traffic lights, the smoke goes in reverse, indicating a reverse footage shot. (01:05:55)
Audio problem: When Billy is playing on the keyboard with Gizmo, the second key we see him hit should have been a higher tone, not lower, as it's toward the right end of the keyboard.
Revealing mistake: When the cops watch the guy in the Santa costume being attacked their brakes are cut under the car but a few moments later when they drive off down the street they do apply the brakes to stop from the lights exploding above and the brakes do work.
Suggested correction: A cut brake line would not stop the brakes from working instantly. It would take a few pumps of the brakes for fluid to expel. So the brakes would work for a little while.
Continuity mistake: When Rand Peltzer is in the gas station office with the gas station attendant, the view from the outside looking in shows the station attendant taking a drag off a cigarette with his left hand, but the next scene shot shows his left hand on his desk and reaching for a cigarette tucked in his right ear with his right hand.
Revealing mistake: When Stripe spits at Gizmo who was playing the trumpet, check for a little Gremlin behind lying down. When he raises his back a big hole is visible where the puppet is moved.
Continuity mistake: In the department store, Stripe is throwing radial saw blades at Billy, and decapitates a store mannequin twice. Further, the separated head falls off the body twice.
Continuity mistake: When the gremlins are driving Mr. Futterman's snowplow towards his house, it comes to a stop, but the next shot from the perspective of the gremlins in the cab show it still moving.
Continuity mistake: The fan the Gremlin is swinging on changes direction between cuts.
Continuity mistake: When the tractor drives into the house, first it's going slow, then travelling at nearly cruising speed.
Deliberate mistake: When the Gremlins take the tractor, from inside, the plastic around the cab is clear for visibility, but seen from outside, it's all black or opaque to hide the stunt driver.
Revealing mistake: As the second Gremlin in the kitchen is flinging dishes, the control rods attached to the puppet's left arm is visible.
Other mistake: Rand demonstrates the supposedly new razor attachment on the Bathroom Buddy. However, it was already on the device in the beginning.
