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: At the beginning, when one bad guy is sitting on a bench with a newspaper, we can read the date October 21, 1959 at the top. But, we also read Nov 3 1970 on the same page, under the mugshot of the Boss being released from jail. (00:04:20)
Continuity mistake: During Stoick's funeral Hiccup first shoots an arrow towards the ship and then the other characters draw their bows. Gobber is not shown as he is further away. In the next shot where they shoot their arrows, Valka and Eret are suddenly further apart from each other and Gobber has moved closer in between them. Eight arrows are shot simultaneously, but only seven arrows rain down.
Continuity mistake: Just before seeing Principle Celestia, and they are walking down the hallway, the cutie mark on Sunset's shirt disappears.
Continuity mistake: After cutting through Black Manta's gun, Aquaman then slams Manta in the face with his trident and knocks him down. As he is twirling his trident in victory, you can see his belt and its design. But then it cuts to a close up of Aquaman and suddenly his belt changes in design with the bar in the middle disappearing and the black of his pants extending further up onto his orange shirt in the belt area. (00:03:50)
Plot hole: The main plot of the film involves Iris and Olson's mission: Destroying the Mobile Fortress 000. But Iris is a special gynoid. Her primary function is to activate the Mobile Fortress. The antagonist of this film could unleash calamity if he had Iris and the fortress. So, which idiot has sent Iris on this mission? The logical course was to send a demolition team, or better yet, send no-one at all. Anything is better than sending the activation key outside the safety of the Olympus.
Factual error: After Batman hits the Manbats with his sonar batterangs and they go nuts trying to escape the sound, some begin chewing at the glass separating them from the ocean in their desperation. This is in the under workings of an oil rig out in the ocean. Hundreds of pounds of pressure is on that glass. The Manbats chew through the glass, and then the water begins rushing in. All logic and laws of physics dictate that the Manbats would be pushed back, down into the oil rig further as water rushes in. However, as the water begins pouring in, 3 Manbats are somehow pushed out of the hole into the water, and are sitting still, long enough for a shark to grab one. Even if they did somehow manage to get out like that despite physics, the water rushing in the hole would have caused a vacuum and sucked them right back in. Yet they remain perfectly still in the water, only a couple feet or so away from the hole they just made.
Factual error: The unit on Dusty's torque dial appears as FT/LB (i.e., FT divided by LB) which is incorrect. FT.LB (i.e., FT times LB) is a unit of torque.
Continuity mistake: When we first see the male volcano, he is an entire island with trees and forests. After many years have passed and sinks into the ocean, it can be seen the trees and forests have now gone. However, after he spews out of the ocean and is together with the female volcano, the male volcano suddenly has trees and forests around him again.
Continuity mistake: During the "Perfect Puppy" silly song, Bob places a newspaper he had been reading on the couch beside him when Larry starts singing. When Bob shows Larry the picture of the dalmatian, the newspaper has vanished. When the shot cuts back to Bob, the newspaper has returned. (00:16:55)