Continuity mistake: In the Scene where Eragon is hunting in the woods there is a shot of Eragon with an arrow in his bow ready to shoot, then a shot of the deer standing still and then it comes back to Eragon who now has no arrow in his bow and proceeds to draw one from his quiver. (00:04:05)
Continuity mistake: At the beginning of the movie after Eragon fires the arrow and the egg appears, flames can be seen around the egg in the wide shot. In the close-up of the egg, these flames are gone. A moment later after the scene with Arya and Durza, the flames can be seen again around the egg as Eragon approaches, then they're gone again at the close-up (as "Based upon the novel by Christopher Paolini" appears). (00:05:00)
Continuity mistake: When Eragon and his cousin are play-fighting in the shed, a large sweat stain appears and disappears on Eragon's shirt. It's there when he kicks a pile of sticks at Roran, completely gone when he picks up the stick he uses as a sword, and then it reappears at the very end of the fight. (00:09:35)
Other mistake: When the baby dragon is hatching, the chip in the egg doesn't match where the beak is, and the body should be perpendicular to the way it faces, it couldn't have fit the way it does. (00:13:40)
Revealing mistake: When the dragon is hatching, a light bulb is visible just behind and to the left of her egg. (00:14:10)
Suggested correction: What appears to be a light bulb in the wide shot is actually a leather strap attached to a larger leather item. This can be seen more easily in the close up shot in the moment after the egg fully breaks.
Continuity mistake: Saphira bites the pouch, spilling milk all over the floor. However in the next shot, the floor is completely dry and there is no spilt milk evident anymore. (00:16:25)
Visible crew/equipment: When Eragon is helping his dragon learn to fly the shot from the sky looking down at Eragon shows car tracks in the grassy area around him. (00:21:45)
Continuity mistake: Eragon leaves his home without his bow, but later on in the story he suddenly has it again. (00:30:20)
Continuity mistake: Eragon's horse has repeatedly different facial markings throughout the movie. (00:30:40 - 00:40:10)
Continuity mistake: Right before Eragon fires his exploding arrow at the attacking Urgals, there are two separate camera shots indicating Urgals attacking from both sides of the bridge - one shows Brom running from them, and the other one doesn't. As Eragon nocks the arrow, it is clear that there are no Urgals behind him and he wins the battle by firing the arrow forward. (00:45:15)
Continuity mistake: When Eragon goes on his second flying lesson using a saddle for the first time, Brom is seen riding his horse. It shows him with just his horse for a few shots, then all a sudden he has both horses when Eragon starts using his "dragon-vision." (00:47:20 - 00:49:30)
Continuity mistake: When Eragon shoots Durza on the forehead with an arrow, the depth the arrow penetrated changes three times. Average depth first, near full depth next, and finally very little just when Durza fades away. Also, the arrows between shots are different, one uses flight vanes at 45ยบ angle, the other uses opposite flight vanes. (01:03:20)
Continuity mistake: Right before battle, Nasuada is showing Eragon Saphira's dragon armor. The helmet is full face, with two little slits for eyes. When it shows Saphira wearing it, the helmet covers only the top part of her head and cuts off above her eyes. (01:20:35 - 01:22:30)
Revealing mistake: When they show the pile of bodies after the final battle, some of the dead soldiers are wearing modern shoes with rubber soles that would not have been available during the Eragon's time. (01:32:05)
Continuity mistake: In the scene just after Brom says, "Death is nothing to celebrate," look closely at Eragon. He suddenly has half a mustache. In other shots and scenes, it's gone. Where did it go?
Continuity mistake: When Eragon and his uncle are talking while brushing the horse, between shots, Eragon keeps changing from holding to not holding hay.
Audio problem: There are several times in the film when Brom and Eragon can be seen mouthing the words "he" and "him" when referring to Saphira. This is most obvious in the scene where they have fled from the Ra'zacs and get off their horses.
Continuity mistake: When Eragon wakes up from one of his visions with Arya, there is a pair of legs behind him. The camera turns away to face Brom, and when it returns, the legs are gone.
Continuity mistake: In the scene where Eragon is talking with his uncle while brushing the horse, the light that hits his uncle's face on the right side(seen when the shot is from behind the uncle) disappears when the shot changes and we see him from behind Eragon.
Other mistake: The front cover for the movie shows Eragon holding a sword with a blue sapphire pommel (brisingr) when he should be holding z'aroc with a red ruby pommel.