Continuity mistake: When Lou and Nick are playing pool in the bar, Lou goes to break the rack and misses. When Nick goes to break them, the balls are racked in a different pattern. (00:50:10)
Other mistake: Near the start of the movie Jon indicates that he has titanium in his right arm, but towards the end of the movie the bullet ricochets off his left arm. (00:08:55 - 01:34:45)
Continuity mistake: When the WABAC machine is going through the time vortex, trying to escape from the black hole, some tiles get sucked off the WABAC, but in the next shot they are back on.
Factual error: The movie takes place during the 1990s, but throughout the movie cars are shown with Illinois license plates with "Illinois" written in cursive. These plates were not introduced until 2001. (00:24:45)
Visible crew/equipment: Near the end, when Rodmilla and her daughters are requested to appear before King Francis, in the first shot facing the king and queen, there is a beige narrow mat in front of the large patterned rug, which is not in previous or following shots, specifically used for crew/camera tracking. (01:50:30)
Continuity mistake: In the scene where John is peeing off Stifler's balcony, he knocks over a plant and knocks out Christy. In the next shot the plant is back, and in the one after that it is gone again. (00:17:15)
Continuity mistake: The morning after Vivian's first night at the hotel, room service brings breakfast. When she's eating a croissant it cuts to a shot of Edward, and when it cuts back to Vivian she's eating a pancake which goes from being half done, to being a whole pancake again. (00:30:55)
Continuity mistake: When Marty chases after Biff on the borrowed 'skateboard', Marty is wearing a dark grey belt and a red/blue print shirt under his red/beige jacket. However, when Marty is hanging on to the front of Biff's car as they turn a corner (and in another shot), Marty (stunt double) is wearing a light brown belt and solid tan shirt. (01:07:00)
Revealing mistake: Gracie hugs the Russian waitress in order to have a better view of the disc hand-off appear on the monitor. As she raises her left hand that holds the book/camera lens, we see that the digital feed that appears on the monitor stays steady and level, even though she is raising the book/camera lens higher and closer to her face. Obviously the feed that we see on the monitor is not taken from the book/camera lens. (00:04:10)
Continuity mistake: The chutes that Wednesday and Pugsley use changes positions when Fester chases Wednesday.
Other mistake: Even though it is snowing throughout much of the movie, none of the snow seems to stick to any of the characters' fur. Even during the fight scene when they are rolling around in it, they are never covered with white.
Visible crew/equipment: When a gremlin attacks the Mum from a Christmas tree, and the tree falls on top of her, you can clearly see a member of the crew with eyeglasses, wearing a red shirt, standing behind the tree pushing it forward on top of her. (00:54:30)
Continuity mistake: During the scenes at her Mother's house, Kate's hair goes from blonde to REALLY blonde.
Factual error: When the barracks are completely flooded, Eggsy uses his bare fist to punch through a large two-way mirror to escape. The fact is that any glass (or plexiglas) thick enough to contain hundreds (or thousands) of tons of water without bursting would be as impenetrable as concrete to Eggsy's bare fist. He would need a chisel-tipped jackhammer to penetrate such a mirror.
Plot hole: There are six metal bars mounted around the circumference of the water wheel's axle. In the wheel's interior, when Jack frees himself he lands on his feet, begins to run and promptly hits his head on one of those mounted axle bars, then falls out. Moments later, when Jack returns and runs in the wheel, he is shorter (way more than a foot) than all six of the mounted axle bars spinning with the water wheel, which would make that previous shot impossible, however humorous it is. (01:52:40 - 01:53:55)
Continuity mistake: When Hal's co-workers bring him a cake for his promotion, Rosemary takes a slice out for herself. They change shots a couple times, and the size of the piece missing from the cake changes several times, and the layers of the cake change as well.
Other mistake: The envelope with the letter for Amanda is suddenly in a very good condition as it ends up in the peanut bowl... even though it has been in the trash, had chewing gum attached to it, been trodden on, had a beer barrel rolled over it, etc....
Continuity mistake: At the beginning of the movie, Harry's van has bucket seats, yet later on when the "gas-man" rides along, he is sitting on a bench seat in-between Harry and Lloyd. (00:38:00)
Suggested correction: Mental isn't sitting on a bench seat, it's implied he's sitting on the floor of the van in between the both of them. Although hard to see, the backs of the bucket seats can still be seen behind Harry and Lloyd at certain points. You see a fair bit of it behind Harry whilst he's dancing as Lloyd sings the line "and if that mocking bird don't sing".
Plot hole: Ted calls on John to tell him that he saw Lori leaving her apartment with her boss. How did he find him? He turns up not only at the right hotel but the right room! They have had no contact since their fight after the party and Ted hasn't been asking around after John as he tells him he 'just saw' Lori leaving with her boss. So how did he find John? Is he psychic?
Suggested correction: A week has passed since the breakup and we don't see anything that happened during that time. There's nothing in the film to indicate Ted didn't try to reconcile with John (such as through text) or at least find out where he's staying. The only reason Ted decided to go to the hotel is to tell John about Lori leaving with her boss because he knows that would be a big deal to him. And Ted went to Lori's to try to get her to take John back (probably because of things John said to Ted during the week we didn't see). Once Ted is at Lori's and sees her leaving with her boss, he goes to the hotel to tell John he "just saw her leave" with him.
John had no reason to tell Ted where he lives, he didn't want him to come at all, that was shown. Ted wouldn't know where to go.
Character mistake: When Stuart calls home from the pay phone he's talking into the wrong end of the phone.