A Stegosaurus kills a young Diplodocus with its tail-spikes (no wounds are visible however) but in the following shots, its corpse magically disappears.
When the Stegosaurus roars at the Allosaurus after pumping blood into its plates, the plates are suddenly back to their normal color.
When the Ornitholestes walks past the camouflaged baby Diplodocus, it's missing its quills.
The Ornitholestes makes loud vocalizations while swallowing food. It is impossible to do this at the same time.
The narrator states that Diplodocus can grow to over 40 m long. In reality, Diplodocus barely reached 30 m. Scientists now believe that a similar dinosaur, Seismosaurus was actually a larger species of Diplodocus, but even then, the animal wouldn't have grown so big.
The crest of the Allosaurus is shown directly above its eyes, but in reality, they were situated lower, in front of the eyes, and they had a pair of smaller crests running down their snout. This was corrected in later follow-ups of the program, but it's an error here.
During the Diplodocus mating scene, the male's legs pass through the female's back spikes.
Sometimes when the Diplodocus open their mouths, their upper teeth "stretch" down below the line of the upper lip. When their jaw is closed, the teeth "shrink" back to being normal-length. It seems the jaw-moving animation somehow got carried over to some of their teeth. This error also appears in the special Allosaurus: A Walking with Dinosaurs Special (2000).
When we first see the Allosaurus, one of the two steps in a puddle without creating a splash or even noticeable ripples.
The leaves and branches disturbed by the Diplodocus hatchlings, as they make their way into the woods, are not actually under their feet but several feet away from them - they are apparently disturbed by nothing, as if the computer generated animals had been animated in the wrong place.
Some water reflections of drinking CG dinosaurs don't match up.
In a forest scene, a young Diplodocus makes drinking motions while eating a bush.
In one shot in a forest scene, a bush keeps shaking as if still being eaten from after the young Diplodocus has stopped eating.
During the attack scene at the end of the episode, the flesh on the side of the Allosaurus' tail moves in unison with its leg. While in reality, the thigh muscles of these animals probably did connect to the tail, the animations shows it shifting position unrealistically, as if the muscle and skin detached from the tail bones.
The front right leg of both Brachiosaurus move very choppily.
In the last shot, the Diplodocus that's farthest away and to the right isn't walking like the rest of the herd. It looks to be walking in place or walking backwards.
After the Anurognathus flies off from the Diplodocus' back in the close-view shot, a strange white object is very clearly visible in the upper right corner of the screen.
In the very last shot, the spinning rotor blades of the helicopter carrying the cameraman can faintly be seen on the top of the screen.
The narrator claims that the Sauropods went into decline during the Jurassic, but that is not exactly true. While they received competition from other dinosaurs in the Northern Hemisphere, they were still very successful overall, especially in the Southern Hemisphere, and that was when their largest species evolved.