Audio problem: When Nighthob and Teeny are talking to the Rockbiter near the beginning of the film, Teeny says to Nighthob "This could be serious", then turns to Rockbiter and calls out his name. Watch Teeny's mouth as he calls out "Rockbiter". You will see a very blatant editing mistake as Teeny is not actually saying 'Rockbiter", but is saying the next line that follows.

Continuity: When the warrior in armour is knocked down by the rays that the Sphinxes shoot, the warriors shield and sword move their position between shots. The shield reverses and the sword moves closer to his body.

Continuity: Atreyu climbs up a tree and talks to the Ancient One. There is a series of face-on shots of the boy alternating with ones from behind him. In the face shots, Atreyu's left hand is below shoulder height on a branch. In the shots from behind, his left hand is holding the branch well above head height.

Continuity: When Atreyu is washed up on the beach, his chest is covered in sand. He stands up, and suddenly all the sand has disappeared.

Continuity: Atreyu gets a spot of mud under his right eye after losing his horse in the swamp. In the subsequent scenes, there is a (different) blob of mud on his face, and it changes size from shot to shot.

Revealing: Watch very closely when the horse is waking up Atreyu. It seems to be searching for something behind Atreyu, then you can see something white fall from behind him, looks like sugar.

Revealing: Support stick for asteroid masks verticals section.

Continuity: Atreyu rests by a stream and his horse walks over to nuzzle against him. The horse does not have a proper girdle to hold the saddle on. Later, when he's riding across the sandy desert, the horse does have a broad girdle.

Continuity: After Hathaway leaves Rockbiter, a large wall of rocks is not there.

Factual error: When Bastian enters his school, it can be easily identified as a modern concrete building. But the attic where he reads the book is (or rather, should be) that of an older building (1950's or even older) - no modern edifice of that size would use old wooden rafters, walls and roofing.

Deliberate "mistake": When Atreyu is talking to Morla, Morla keeps sneezing which keeps throwing Atreyu off the tree, but in one shot, right before Atreyu falls off, apparently it's his stunt double.

Revealing: When Atreyu is holding on to the tree as the Nothing attacks, you can see a string on his leg right before he yells out "Falcor!"