Continuity mistake: When Fairy Godmother is throwing the books behind her, the book "Snow White" lands on the other books. "Snow White" noticeably changes position between two shots. (00:41:15)
Continuity mistake: When everybody goes into Branch's bunker the King is wearing clothes. A few seconds later during hug time he only has on underwear.
Other mistake: When the switch is thrown to electrocute Terrence and Phillip, it's pulled downwards. A few shots later, we see Cartman jump in to save T and P by turning the switch off. He also pulls the switch downwards instead of pushing it upwards. (01:06:05)
Plot hole: Scar tells the pack he didn't make it to the gorge in time to help Mufasa. However Zazu was with them at at the gorge. He could have easily told Serabi or any of the other lions on the numerous times he spoke with them, exposing Scar.
Suggested correction: Actually, Zazu wouldn't honestly say that Scar was lying; he left Scar at the gorge, but for all he knows, when Scar talks about not getting to the gorge in time, Scar could just mean that he couldn't find a safe path into the gorge to help Mufasa and Simba escape.
So Scar would say he couldn't get to Mufasa in time. Not the gorge.
Continuity mistake: At the beginning of the movie, Itchy comes to heaven in a teal colored shirt. When given a halo, he is in a blue shirt (the shirt is for heaven, but not given to him at that moment). When Itchy runs to Charlie right after that, his shirt is teal again. When Charlie tells Itchy he is dead, that's when the shirt changes to blue again (purposely).
Other mistake: When Nebbercracker is on the stretcher and is being wheeled away, the grass pulls off one of the last wheels. When the stretcher is loaded into the ambulance both of the back wheels are intact.
Continuity mistake: Tony Trihull appears when Finn McMissile begins chasing Professor Z. It also shows when Tony uses his magnet. When it is used, Finn's equipment are pulled by the magnet, which includes his bullets. Those bullets are black when all of them were going out. However, when they are pulled onto the magnet they are grey.
Audio problem: On the first level of the video game, after Velma brings up what she remembers what Eric said about the Scooby snacks in the game, you hear Daphne talking but you see Velma's lips moving. (00:01:00)
Continuity mistake: Lotte barges in the pizza place and carves her name onto Shaggy and Scooby with her sharp nails. LOTT on Shaggy's shirt, and the E in Scooby's fur. They run out the door and then come back to pay for their food. Suddenly the rips in Shaggy's shirt and the scraped off fur on Scooby's chest have vanished. (00:23:45)
Continuity mistake: Before Smee gives Hook a shave they hear Tick-Tock Croc approaching, and when Hook nervously spins around to look at the water, note that he has a left hand and his hook is at his right, but it should be the opposite way. (00:24:20)
Continuity mistake: In the scene where Grug is chasing after Guy, they both wind up stuck in a tar pit. After successfully escaping they are covered in tar and Grug even gets himself stuck to Guy. In the next scene everyone is running from the exploding ground up between the mountains and both Grug and Guy are completely clean and free of tar.
Audio problem: When Oh and Tip are searching through the crashed Gorg drone, Pig's meow is briefly heard, but he is not with them.
Factual error: The main character from the video game "Paperboy" is among the alien invaders in the final battle; since that game was first released in 1984, he shouldn't be there, because the probe the aliens received featuring video game footage was launched into space in 1982.
Continuity mistake: After Dory reads the wall map while she's in the glass carafe, when Hank hides behind the rolling cabinet there's a long shot of the corridor with him at the far wall, then in the next shot from behind Hank a drinking fountain has suddenly appeared on the wall to the left between two pictures.
Deliberate mistake: In the scene where Emmet drives to work, you get Emmet's view of the dashboard with his hand switching on the radio. The car at that moment has no front window, perhaps to make the car look bigger from the inside. (00:04:50)
Other mistake: During the Battle of Teth (the pillared jungle planet), the AT-TE's shoot the ledge at the top and there's not a single mark on the ledge afterwards, despite being hit with several joules worth of fire.
Plot hole: Joy and Sadness are stuck outside of the control center. They are trying to figure out how to get back, and encounter maintenance workers who are discarding old memories. The maintenance workers show that they have the power to send memories back up to the control center to be played. Why couldn't they send the core memories that Joy had back up the same way? Better yet, why not use that method to send Joy and Sadness back up to the control center? The director of the film is even aware of the plot hole, and said "Yeah, well then we wouldn't have a third act," before explaining how the idea of recalling memories was added in later, "box[ing] [the screenwriters] in a corner a little bit."
Suggested correction: Even if they do send the core memories up to headquarters, they wouldn't be able to get joy and sadness through the tiny gap that the workers send the memories up. Joy has to be in headquarters for Riley to be happy.
This mistake is large enough that the director is aware of it. I think that more than qualifies it to be on this site.
Continuity mistake: In the scene where Aladdin is talking to Jasmine in front of the mirror the jewelled flower is in a vase with a real flower when the monkey under the table takes the real flower and the scene cuts back and shows the vase with both flowers. Seconds later the vase is completely empty.