In this episode, Gravity Falls is shown to be in the center of Oregon, but in subsequent episodes, Gravity Falls is shown to be in Eastern Oregon.
Corvallis is spelled "Corvalis" on the map of Oregon.
One man in Stan's tour group sports a camera bag around his shoulder. After Stan shows the group the Sascrotch, the camera bag disappears.
While Dipper is reading from Journal 3, he reads "studying" even though the book says "researching."
The triangle stained window is centered with a double ring from the inside, but from the outside it has a single ring.
When Dipper is showing Journal 3 to Mabel, the page Dipper wrote at the end of the episode can be seen, even though he hadn't written that page yet.
The order of the pages in Journal 3 are different from the first time Dipper opens the Journal and when he shows Mabel the journal when he attempts to convince her that Norman is a zombie. The book's introduction is shown to follow the page that says "TRUST NO ONE," when in actuality the introduction is at the very beginning of the book.
When Dipper and Mabel are being chased, a rear shot of the back of the Mystery Cart shows that Dipper's hat is missing despite it being present in the preceding and following shots.
The initial scene, where Dipper and Mabel crash out of an outdoor and Mabel struggles not to puke, doesn't appear when they were actually being chased by the gnomes.
After Dipper throws the shovel at the gnomes, the crashed Mystery Cart changes positions.
When Mabel accepts the engagement ring from Jeff, leaves appear in her hair. The leaves disappear in the next shot.
Corvallis is misspelled. Gravity Falls is shown in central Oregon.
Gravity Falls is shown in Eastern Oregon in "Scary-oke" and "A Tale of Two Stans."
The tall bald man has a camera bag around his shoulder.
The bald man's camera bag is missing.
Entry reads "researching."
Shadow has two rings in the center.
Introduction is shown to be in the middle of the book.
Dipper's entry has not been written yet.
Mystery Cart originally is directly in gnomes' path.
When Old Man McGucket says "Aw, banjo polish!" when leaving the dock, his mouth doesn't move.
In Mabel's fantasy, Xyler initially has blue-framed sunglasses, and Craz has pink-framed sunglasses. After Mabel talks to them, they both have pink frames.
When Soos grabs Dipper by the top of the life-jacket when they are running away from the Gobblewonker, one shot shows Dipper's shirt pulled up by the life jacket, exposing his stomach. However, in the next shot, his shirt is not pulled up.
When Soos is throwing the cameras at the Gobblewonker, some cameras randomly appear in his hand.
When McGucket shows the first newspaper article, it has the subheading, "Now with less typos." In the next shot, the subheading says "Now with less typo."
Craz's glasses change color
All letters on Mabel's hat are purple and all letters on Dipper's hat are blue.
When Mabel says "Even us!" the button on her disposable camera disappears.
Dipper and Mabel make a scribbled line on Mikey R.'s row on their checklist. However, in a later scene, this mark is instead shown on the Angry lady's row.
When the security footage of Toby is shown for the first time, the clock starts at 10:00 with the seconds ticking off. However, the second time it is shown, the clock still says 10:00 and the seconds are reset at 0.
When Wax Sherlock Holmes decapitates Wax Stan and he looks at the head, the design on the fez is a simple crescent, rather than the actual design.
The wax figures say they come alive during a waxing moon, but the moon shown during the fight between Dipper and Wax Sherlock Holmes is waning.
Larry King is almost as tall as Sherlock Holmes.
Larry King is much shorter than Sherlock Holmes.
Multiple colors but one pencil.
The time is ten minutes and five seconds.
The time is ten minutes and five seconds again, despite time having passed.
When Gideon sings to Mabel during his performance, Mabel is missing all but one tooth for a shot.
In the exterior shot of the Mystery Shack before Mabel shows Dipper her makeover, the sign on the Mystery Shack's roof says "World Papov" instead of "World Famous."
Before Mabel shows her makeover to Dipper, Dipper's book appears to be Journal 2 instead of 3. The book labeled 2 belongs to Gideon Gleeful, so this is impossible. Alex Hirsch acknowledged that this was, in fact, an animation error.
When Mabel shows Dipper her makeover, Dipper sets Journal 3 on the chair, but when Soos enters, the book is gone.
When Dipper and Mabel are playing video games, Mabel's sweater collar has stripes on it for one shot, but not in any other shots.
The photo of Dipper and Mabel that Gideon burns is not on his door in any of the preceding shots.
When Dipper and Mabel are playing with Soos, Mabel is wearing a sea foam green headband, which turns red when the phone rings, then back to green in the following shots.
The three journals all have 4 gold corners on the front cover in each corner. When it is revealed at the end of the episode that Gideon has Journal 2, the bottom left corner is red instead of gold when he closes the book.
During the end credits, there are a number of errors.
When Soos spins to the side with no jewels on it, the wall still has the disco ball effect.
The light reflections rotate in the opposite direction Soos is spinning.
The lights on the wall travel much slower than Soos is rotating.
Dipper high-fives Wendy with his right hand, but in the following shot, he is using his left hand.
When Dipper is pretending to write something down, the pen switches from his left to right hand with each shot.
Tambry is not present in the minivan when Thompson drives the gang to Dusk 2 Dawn, even though she is seen getting into the car.
When Mabel says "This is going to blow someone's mind," the pine tree on Dipper's hat is outlined in black.
The fence surrounding the Dusk 2 Dawn changes height from shot to shot.
When Dipper is trying to climb over the fence, Lee is on the same side as everyone else, the same side as Dusk 2 Dawn. However, before he pushes Dipper off the fence, he seems to be climbing from the outermost side of the fence, as if he were going in.
When Dipper is opening the vent to get inside, Tambry's leggings vanish for a shot.
When the newspaper is on the stand, the title reads USA WEEK, but when Dipper rubs off the dust, the title says USA NEWZ.
When Nate and Robbie are putting ice in Thompson's pants, Robbie is missing his pimples and piercings, and his nose is the same color as his skin.
When the three teens' reflections are shown in the window as normal, Tambry's reflection is smiling, but Tambry herself is not.
In the same shot, Tambry's leggings are missing.
Robbie's reflection is not mirror-imaged.
Wendy's mouth is not mirror-imaged.
The open/closed sign is missing from the door.
Thompson parks the minivan outside the fence when they arrive, but when Pa opens the doors, the minivan is inside the fence. When the teens leave, the minivan is outside the fence again.
Ma and Pa Duskerton collapse from heart attacks by the window near the front door, but their bodies are chalked near the end of the store.
In the chalk outline, Ma's arms are sprawled out, but when she dies, her arms are on her chest.
When Thompson is first seen playing Dancy Pants Revolution, the arrow that points left is white. When he gets trapped in the game, it is pink.
When the teens are booing Dipper for not wanting Nate to lie in the chalk outline, Robbie's guitar is on the side of the desk with the cash register. In the next shot, the guitar is in front of it.
Ma's name tag is missing when Dipper does the Lamby Lamby Dance.
When Wendy is telling everyone about how Dipper saved them, the mud on her boots is at the top, but in another shot, the mud is on the bottom of her boots. In the same scene, Dipper's nose is the same color as the rest of his face for a shot.
Also, Robbie's nose is the same color as the rest of his face in one shot.
The open and closed sign changes from open to closed many times in different scenes.
Tambry is nowhere to be found.
Robbie is missing his pimples and piercings.
Numerous errors in the mirror
Guitar behind the counter
Guitar at the front of the counter
Died near the window, chalked at the back of the store
Dipper's nose is miscolored.
Mud on the top of her boots; Robbie's nose is miscolored.
Mabel's nacho earrings appear and disappear from shot to shot.
When Stan threatens Toby Determined, the line between his eyes (part of his glasses) disappears.
When Gompers is at the wedding ceremony, his right horn is broken instead of his left horn.
When Sheriff Blubs is announcing the commencement ceremony, there is no microphone in front of him. A microphone appears in the next shot.
When the Northwest family has their picture taken, the Nathaniel Northwest statue changes from facing left to right.
When Dipper and Mabel are reading from the Journal in front of the statue, the statue is shown to face the same direction as the name plate on its base. After Dipper and Mabel leave, the name plate has shifted positions on the base.
When Dipper removes the document from Journal 3, Mabel's blush marks disappear.
When the twins exit the museum, the right hand door is open; however, when the officers leave, the other door is the only one open.
While in the vault, Quentin Trembley's mouth is open. However, in the following scene, his mouth is closed.
The crate the twins and Trembley are trapped in has a roof, which disappears when the woodpecker disassembles the crate.
When the twins and Trembley are inside the train, a window in the back of the train shows them in the rear car. However, when they exit through the roof, there is another car behind them.
When Dipper is running towards Pacifica to tell her about Quentin Trembley, Mabel's headband disappears.
When the Unnamed hillbilly throws balls at the dunk tank, his right hand is shown with no half-finger missing.
When Dipper is explaining to Mabel how he asked Wendy to go to the fair with him, he has a question mark corn dog. However, after the flashback to Wendy saying she'll go to the fair, the corn dog is gone.
When Wendy first sees the stuffed animals, they are seated on a board, but in all of the other shots, they are hanging on a rack.
When Waddles is dressed as a doctor, for one frame his nose is the same color as the rest of his face.
When Blendin's "position is compromised" after he fails to hide, his watch switches from his left hand to his right hand.
When Dipper asks Mabel if Blendin's explanation is making any sense to her, his hat is a noticeably different shade of blue.
When Blendin walks to the barrel ride, the flower in Mabel's hair vanishes.
When Blendin walks to the barrel ride, the time machine is not on his belt. It reappears in the next shot.
When Dipper and Mabel high-five each other in the Mystery Shack, Mabel's braces and dimple marks are missing.
When Mabel is riding the Ferris wheel with Waddles, the ticket booth in front of the Ferris wheel is facing to the right. In all the other "do-overs," it is facing toward the front.
After the fire from the first do-over creates a mark on Dipper's hat, it remains there for the rest of the episode. In some shots, however, the burn mark disappears. For example, the burn mark is not present while Dipper is doing calculations on the glass.
The caramel apple that Mabel feeds Waddles disappears after she drops it.
Mabel's eyes are parted in the middle in one frame.
When the twins travel to opening day of the fishing season in "The Legend of the Gobblewonker," the sign says "Fishing Season," but in the actual episode it said "Fishing Season. Opening Day."
In the flashback of the events of "Headhunters," Pizza Guy is wearing a green shirt, but in the actual episode, his shirt is red.
When Robbie talks to Wendy in Dipper's final do-over, there is a frame in which his teeth are skin-colored instead of white.
When Dundgren is talking to Blendin, there is a frame in which his pupil is colored light green instead of black.
Dipper's corndog disappears after a few shots.
The stuffed animals change locations.
Watch changes hands.
Dipper's hat is a different shade of blue.
Mabel's braces are missing.
Inconsistent ticket booth orientation
Missing burn mark
Mabel's eyes are separated.
Robbie's teeth are miscolored.
The sign says "Fishing Season."
The sign actually said "Fishing Season Opening Day."
Robbie has five fingers on his band poster, even though he has four in every other appearance.
When Stan complains that Mabel doesn't know what game they are playing, Mabel's mouth closes without any animation.
When Mabel wins the crackers in the card game, nobody else had any. However, in the next scene, Dipper and Stan both have more crackers.
When Robbie pushes Dipper down and then walks away, the trash cans and Dipper's hat disappear. They then reappear when Stan comes out.
When Dipper is playing Fight Fighters after Robbie threatens to fight him, he starts the character selection with Dr. Karate of Japan and Beastor of Brazil. When Dipper scrolls away from Beastor, the character's geographic dot vanishes from the world map and does not return. For most of the scene, there are eight characters, but only seven geographical locations.
As the character selection scene continues, Dipper moves the selector to Joe Zambique of Mozambique. The geographic dot is much too far north for Mozambique, even by the loose standards of the distorted world map. But the dot moves southeast to the correct geographic location when Joe Zambique is temporarily selected. The dot returns to its previously incorrect location as Dipper continues to scroll through his character choices.
When Dipper is following the instructions "to unleash ultimate power," the moves he says to himself are different from what appears in the instructions.
When the Fight Fighters game turns off before Rumble comes to life, Dipper's hat turns solid blue.
When Stan sees the skydiving show, his mouth animation is shown in two places simultaneously for one frame.
When Stan falls backwards away from the TV, he trips over the dinosaur skull onto the floor. However, the wall is usually too close to the dinosaur skull for Stan to be able to lie on the floor behind the skull.
While walking to Circle Park, Dipper and Rumble pass a barber shop and walk in front of a eat shop. When Rumble picks up a pipe, they are suddenly back in front of the barber shop. In the following shot, they are in front of completely different buildings.
Mabel has all the crackers.
Dipper and Soos now have some crackers.
As seen in "The Hand that Rocks the Mabel", the skull is too close to the wall for Stan to be able to lie behind it.
When Mabel and Dipper are playing chess, Mabel moves a black pawn and Dipper says it is not her color (implying her color is white). He then uses a white pawn to take out the black king.
When Stan knocks the jar of termites out of Gideon's hands, it falls on the porch. When Gideon runs away, it is in the doorway.
When Dipper grows a pawn and it goes through the roof, the weather vane has the normal letters N, S, W and E (the cardinal points) instead of W, H, A and T. Furthermore, these cardinal points are incorrectly arranged (either the N points south or the W points east).
During the flashlight duel, Mabel and Dipper do not flip the crystal, but the beams change from grow to shrink and back again numerous times.
When Mabel is in the bag of Gummy Koalas, her headband is missing for a shot.
In the mirror, Stan's tie is not reflected.
Before Stan places his fez on the dresser, the fez symbol is not reversed in the reflection.
Soos' brown hair is gray in the mirror.
The photo of Gideon on his ID card shows him with only four fingers per hand.
When Dipper and Mabel run across Gideon's neck, Mabel's headband is missing.
When Dipper and Mabel tickle Gideon, the pine tree on Dipper's hat is missing.
After returning from the Summerween Superstore, Dipper and Mabel are on the floor in front of Soos, with many items such as scissors, a pencil, and glue, but when Soos tells them to be careful, these items disappear. They reappear when Soos tells the twins about the Summerween Trickster.
After Mabel finishes talking about previous Halloween costumes, Dipper eats a piece of candy, and while he is choking, there is a moment when the back part of his hat is not blue; it blends in with the wall behind him.
When Dipper is shocked to see Wendy with Robbie, he drops the bowl of candy. In the next shot, he is holding the bowl again and there is no candy on the floor.
Candy's mouth vanishes when Dipper comes downstairs.
A shot of the trick-or-treaters before Mabel and Dipper leave has many errors: Gorney, Candy and Grenda are shown trick-or-treating, even though Gorny was eaten and Candy and Grenda are at the Shack, and Waddles is with some random kid even though he should be at the Shack.
When the kids are looking up at the roof of the Mystery Shack after the Summerween Trickster is gone, they are standing in a line with Grenda to the left of the rest of them. In the next shot, Grenda is standing behind Dipper and Mabel.
In one of the end credits images, Waddles' light brown/tan spot is on his right eye rather than his left.
Candy, Grenda, Gorney and Waddles are not where they are supposed to be.
When Mabel first enters the gift shop with Soos, Dipper and Wendy, the jar has a red line on it. Later, after Dipper leaves, Mabel draws the red line and claims that they will fill the jar with "one hundred billion dollars."
When Mabel is holding the Questiony the Question Mark costume, it is pointed like a normal question mark. When the shot changes to the other side of her, it is facing the same direction, even though it should be reversed.
Tambry's highlights change sides of her head from one shot to the next.
When Mabel yells at Soos and Wendy for not doing their jobs, Wendy's boots are cut off.
When Mabel stands in front of the mirror wearing Stan's hat, the fez symbol is not reversed in the mirror.
Dipper alternates between having neater and messier hair in the scene where Stan returns.
When Stan is telling Soos about the perfect chair, another chair is seen behind Soos, which disappears in a later shot.
The first time Mermando plays his guitar, he seems to be left-handed. But the second time, during the night, he plays it as if he were right-handed. If he were ambidextrous, he would have had to restring the guitar to play it with either hand.
When Dipper gives Mermando "reverse CPR," the water bottle he is using fills back up with water every time he drinks from it.
The fifth message in a bottle Mabel receives from Mermando reads "Lebam," her name backwards.
When Stan says "Nonspecific excuse" on his date with Lazy Susan, the one of the latter's pupils disappears for a frame.
When Mabel closes the door on the memory of Stan's date with Susan, the latter's food is missing from the table.
In the memory of Stan that Dipper enters, when he first enters it Soos' T-shirt is the same color as his skin.
When the memory of the combination falls into the Bottomless Pit, initially Stan is not holding a cane. When it cuts back to him, he's holding a cane.
While watching the memory of Stan explaining why he is hard on Dipper, Dipper is hanging his hand onto the wall in the memory. In a later shot, Dipper has to push through an invisible wall to get into the memory.
During the scene where Bill shows Mabel and Soos their nightmares, Mabel's skin alternates between green and normal-colored after Bill blasts Xyler and Craz away and when Dipper arrives.
When the twins and Soos enter Stan's mind, there are candles around him. When they leave, the candles and his fez are gone.
In the shot where Gideon unveils his Gideon Land model, his white tie breifly turns green. Later, it turns green again when he commands the gnomes to take Dipper and Mabel away.
The tattoos on the bouncer's arms disappear as he grabs Mabel.
When Wendy mounts her bike, the outline around Dipper's right eye is briefly miscolored.
At the exact moment when Gideon tells the gnomes to subdue the twins, his right foot is split in two.
In "Little Dipper," the maze page is the page before the height altering crystals one. In "Gideon Rises," the Gremloblin page is before it.
When Gideon asks Old Man McGucket if the Gideon-bot is completed he has 2 and 3. However, when he enters it, the books are gone. Later, when Dipper and Mabel defeat him, 3 is revealed in the robot, as Dipper found it in the rubble, and Gideon held 2 in his clothes.
In the photo in the newspaper article about Gideon's incarceration, Gideon has only four fingers on each hand.
When Dipper is first shown unpacking, the perspective of his suitcase is wrong and laid over partially on a boxes of crates in the background. In the next shot, it's correct.
When Mabel tells Dipper that he doesn't need the journal, there is a suitcase on her bed. In the next shot, it's gone.
After Soos squirts the twins with water guns, there is a pan-down from the attic to the Mystery Shack. However, the rooms are facing opposite directions.
At the end credits, the TRUST NO ONE page is on the wrong side of the book, as in "Tourist Trapped" it's on the left, not the right.
Gideon's bolo tie makes a surprise cameo.
Gideon has four fingers
Suitcase is the wrong perspective. Sitting on background crates.
The shot is facing out the window.
The shot is facing away from the door, which is on the same side of the building as the attic window.