Gaffes

When Sloth breaks his chains to release himself, he rips them out of the wall. However, you can see from how he is chained that he is not only chained to the wall, but his hands are cuffed together. He does nothing to break the cuffs on his wrists yet when he rips the chains from the wall, the cuffs disappear.

When Andy makes the first mistake on the bone piano, a huge hole appears and Mouth almost falls in. When she makes the second mistake, another hole appears and Brandon almost falls in, but the first hole has gone, and only reappears when the puzzle is solved.

(at around 1h 30 mins) When the kids are jumping off the pirate ship, Data jumps off twice.

When Chunk is drinking out of the cooler, it is almost empty. But when he hits it and grabs it to try to keep it from falling, it is more than half full.

While going down to enter the cave, Data's shoes are white with a black Nike sign. In the next shot he is wearing black shoes and a white Nike sign.

When the Goonies leave the house, they let the air out of the tires of Brand's bike by only taking off the cap. They would have to stay and push down the stem on both tires to make them flat.

When Chunk is on the phone with the sheriff and Sloth pulls out the cord that connects the receiver to the phone, a dial tone is heard on the sheriff's end. Unplugging that cord wouldn't have disconnected the call.

It is nearly impossible for a fired pistol bullet to ignite gasoline.

At the end of the movie, Data tells the news reporters that the "octopus was really scary". This actually refers to a deleted scene, but there's nothing to indicate that he wouldn't just make stuff up and talk about something which (in the final version of the film) didn't happen. The octopus scene is included in the TV version of the movie.

When Andy tries to play the piano, she claims she can't tell if a note is "a-sharp or b-flat," which are one and the same. However, this was probably intentional to indicate how out of practice she is.

When Mouth is translating in Spanish for Rosalita, he says, "La rapidez está en el cajón de abajo," which the captions translate as "speed is in the bottom drawer" referring to the drug methamphetamine. However, in Spanish, the word "rapidez" literally means velocity or speed, and it is not used to refer to the drug.

Mouth is just a kid with an elementary level proficiency in Spanish, he's not going to know the actual name of the drug, and the housekeeper is already overwhelmed with the notion that the room is full of drugs to question it.

The incident with the plumbing makes the water dig a hole in the wall to reveal a secret entrance, however, later in this new tunnel, the kids come across Chester Copperpot's skeleton. Since Copperpot had come that far, the wall should have already had its secret entrance opened. However, the basement with the (in-use) pipes was probably built after Copperpot went looking for the treasure.

The balloon used for the automatic gate changes color from red to pink. The change was most likely a result of the red balloon stretching to its popping point and the stretching made it whiter, meaning it would be pink.

When Mikey's dad tears up the contract and tosses the pieces into the air, another extra bunch of pieces are thrown up in the same direction, a second after the initial throw.

(at around 51 mins) When the pressure builds up and Troy is launched off the toilet by large amounts of water, you can easily see the platform he is sitting on and the pipe that pushes the platform up. Also, he is wearing red underwear on the toilet.

Chunk has a mole on his left upper lip. It's particularly obvious when he is reading about Chester Copperpot in the attic. But when he is thrown into the back of the black jeep, sees the dead body, and screams, the mole is on his right upper lip. It's Jeff Cohen's own mole, rather than a Hollywood mole, leading to the conclusion that the negative was flipped.

When Data starts the printing press, you can see the plates say the number "100" and the word "hundred". But after the press feed the paper though, they come out as $50 dollar bills.

(at around 1h 30 mins) When Sloth swings down to rescue Stef and Mouth from the plank, you can clearly see that there is a mock-up of Stef and Mouth that Sloth is rescuing, not real people.

Onboard the Inferno, Mikey is frightened by something and takes a couple puffs of his inhaler. When he shouts, his mouth doesn't move, and his breathing is audible during the puffs.

In the Fratellis' basement scene, Sean Astin (Mikey) accidentally breaks character and calls Josh Brolin (Brand) by his real name, saying, "There's something buried under there, Josh."

Kids are shown riding their bicycles from Astoria to Cannon Beach but these two towns are 40 miles apart from each other and would be incredibly difficult for kids to cover that distance with their small bicycles.

Mikey uses the doubloon to line up the rocks and light house to locate the treasure entrance. However the light house is clearly modern and the coin was presumably created in the 17th century.

In the Walsh house, when Mouth, Mike, and Brandon tell Chunk all his made-up stories, Mouth tells him about when he said he ate his weight in pizza. Mouth says "Godfather's Pizza," but mouths "Pizza Hut." Pizza Hut refused to be mentioned in the movie, so the shot was overdubbed.

When the Goonies first walk into the tunnel, Andy says "We've been walking forever. How far do we plan on going?" while mouthing something else.

When Troy grabs Brandon on his bike and sends him hurtling off the road, Brandon yells out but his mouth is closed.

When the kids are climbing the rope-ladder onto the ship, a crew member's arm is cueing an event in middle-left of frame.

When Mikey picks up the line of string for the first booby trap, an adult hand pulls at the string first.

Hen the kids are riding down the slides to Willy's ship, working light bulbs are seen throughout the rides.

A camera is visible in the ORV's side view mirror when Mama Fratelli tells Francis to hurry up.

The final scene looks out to sea, with the sun in the background. However, the scene is supposed to take place in the morning, not late afternoon (as it would have to be with the sun in that spot over the Pacific Ocean on the West Coast).

The story takes place in Astoria, Oregon, but the beach scenes are clearly shot north of Cannon Beach, with Ecola Head in the near background and Haystack Rock farther back. Cannon Beach is 30 miles from Astoria, too far for the kids to reach by bicycle to in the time given. Aside from mountain logging roads, the only road connecting the two towns is Highway 101, which carries too much traffic for kids to ride on. Astoria is also about 10 miles east of the coast.

It is not established how the doubloon ends up with Chunk so that the Fratellis are able to find it (but this was probably filmed and deleted because the screenplay indicates that Chunk retrieves the doubloon when the Goonies all fall to the floor after being frightened by Sloth).

The Goondocks are located on the side of very steep hills, a poor location to build a golf course.

When the Goonies are arguing in the basement of the restaurant, Mikey calls Josh Brolin by his actual name (Josh) instead of "Brand," his character's name.

(at around 16 mins) During the attic scene, Data is seen looking at items he turns to Brand and says "don't touch it Josh" referring to Brand as Josh Brolin. Later on in the basement scene (at around 40 mins) Sean Astin picks up a poker and says to Brand "There is something buried under there Josh" yet again referring to Brand's actual actor name.

When the boys ride their bikes to the shore, Mikey drops the map, jumps off his bike to go get it, and leaves his bike in the middle of the road.

A paper the Goonies pick up in the basement of the restaurant has a headline that misspells "Fratellis" as "Fratelli's".