Goofs

Around one hour into the film, when David and his gang attack a group of people while Michael watches on, one of the victims is the punk with a gray stripe in his hair who was killed earlier in the film.

The gate jumps back and forth between broken and mended when the dog jumps against it.

Max's jacket is soaked by the Frog Brothers, but can be seen soon after to be dry.

At the beginning of the movie when Michael, Lucy and Sam stop at the gas station, Michael unloads his bike from the back of the trailer. Then, during the montage of locals from Santa Carla there is a shot of the three of them in the car again, and then shortly after they pull up at Grampa's and Michael is riding his bike.

When the vampire gang awaken to fly to Michael's house near the end of the film, they are bare footed, but when they reach and fly into Michael's house, they all have boots on.

The credits at the end give credit to the poster hanging on the wall in Sam's room as a still from The Breakfast Club (1985). In fact, this picture of Molly Ringwald in a dark blue shirt sitting in a classroom is not from The Breakfast Club, but instead, from Sixteen Candles (1984).

The family is moving to Santa Carla, CA from (presumably) Phoenix, AZ. However in the main titles, as they're driving, the coastline is on their right which would mean they are driving south. If they're driving from Arizona to (again, presumably) Central California, they would never be driving south.

When Lucy is making dinner, she tells Grandpa that Max is coming at 8. It's summertime in California, it should still be daytime around that time, yet when Michael meets Max at the door on his way out, it's totally dark outside.

When Sam wears the concealed garlic necklace to bed with his mother, she exclaims that he smells like garlic. However, the garlic around his neck is still whole in bulbs and would therefore have a very weak scent, if any. It is not until garlic is peeled or crushed that its smell becomes apparent. However, the mother remarks about it sleepily (which is why she didn't stay on the subject), and while the scent would be weak he had a number of them around his neck. There would be a faint smell and that is she picked up on.

Before Star gets on David's motorcycle to go to the cave, she isn't wearing a coat. During the motorcycle processional to the cave, she suddenly appears wearing one. However, she can be seen putting on a coat just before this sequence.

At the end of the movie when the vampires come back to get revenge they never asked for permission to enter the home the way Max did. All vampires must get permission from the head of the house to enter. However, the movie never states that vampires need permission to enter the house. Max tells Sam and the Frog Brothers later on that inviting a vampire into their home leaves them powerless. That's why none of the tricks they tried during the spaghetti dinner worked to reveal Max as a vampire.

David has stubble and even a short beard up to his final fight with Michael before being thrown on to antlers. When Max looks at David's lifeless body, his face is smooth.

When Sam enters Michael's room after his first encounter with the Lost Boys, Sam opens the blinds to let light in. A second later, light starts pouring in from the bottom right corner of the screen from a mistimed light.

There are two dogs playing Nanook. Both have widow's peaks, however, one dog's peak extends into a thin stripe between its eyes. The latter is most noticeable during the bathtub scene.

Shot of the approach to the cave was filmed and then played backwards.

As the wife of the Board Walk security guard posts her missing persons poster, another poster is visible which advertises an event at the Santa Cruz County Fair Grounds. For the film, Santa Cruz was renamed Santa Carla to avoid associations with the city and the film's gang-related themes.

When Sam, Edgar, and Alan find the group of Vampires hanging upside down in the cave, Marko one of the vampires facing towards and facing away from the camera in between shots.

When David is first meeting Michael on the Boardwalk, there is a wide shot in which David is clearly saying something to Star - though no audio can be heard. In the next shot of a close up of David, you can hear and see him saying his line.

When the beach concert star performs his song "I Still Believe," his lips are out of synch to the lyrics.

When Michael is in his room and he begins to float, his harness is visible.

When Michael is closing a window in the kitchen preparing for the vampire attack near the end, there's a crew person reflected in the cabinet glass to Michael's left.

When Sam is singing "Ain't got no Home" in the bubble bath and the camera is looking at his door from the stairs, a shadow of a man standing in the hallway on the right of the screen can be seen on the floor, and it moves right before the scene cuts away.

Sam is supposed to be a serious comic book collector. However, during his first encounter with the Frog brothers in the comic book shop, he picks up several comics at the middle of the spine with enough force to bend the spine of the book, the first one pretty severely. Any comic book collector knows that this damages the book and would never pick one up that way. Also, a comic book shop owner would likely go ballistic if a customer handled books this way, or at the very least not let them handle any more books.

When Laddie bursts out of the bed and runs to the wall, Alan Frog says "Holy shit, the attack of Eddie Munster." Eddie Munster is a werewolf, not a vampire.