The young Tyrannosaurus's teeth are red before they start eating.
The position of the Triceratops carcass is flipped between shots.
The Quetzalcoatlus makes loud vocalizations while swallowing a fish. It is impossible to vocalize and swallow at the same time.
Anatotitan is shown with five digits on its forelimbs. In reality, it only had four - it lacked "thumbs".
Since the Quetzalcoatlus uses the same animation model as the female Ornithocheirus, it only bears a faint resemblance to the actual animal. The head shape is incorrect and it has teeth, which Quetzalcoatlus lacked.
The Tyrannosaurus model suffers from many anatomical errors. It has several bony ridges on its head, none of which are represented on any known fossils. It lacks the scraping teeth from the front of its jaw which is a characteristic of tyrannosaurs. It also lacks the immense neck muscles, also a well known feature of their anatomy. Also, the tail is far too short -- not only is this an anatomical error, the animal wouldn't have been able to stand upright with such a short tail. Considering that Tyrannosaurus was one of the most well-known dinosaurs even when this show has been made, these errors shouldn't exist.
The tail-club of Ankylosaurus doesn't look like what the fossils show, it is far too wide and seems to lack its pointier tip.
When the male Tyrannosaurus starts eating, the meat doesn't go in his mouth, but behind his head.
When the Didelphodon is raiding the nest, its legs go completely through her body.
In some shots the Torosaurs' frills go through their shoulders.
The snake encountered by the young Tyrannosaurs is obviously a modern day python. Cretaceous snakes were primitive and looked different from modern ones, for instance their head looked more like that of a monitor lizard.
In the establishing shot of the Anatotitan herd browsing through some vegetation near the lake, one of the animals in the background stands atop a fallen tree that is still standing out of the earth. It is possible that the Anatotitan in question was supposed to be animated behind the dead tree, not on it - it would be hard to believe that an animal of this size would climb onto such a fragile piece of wood in order to reach some branches that it could reach anyway with ease.
When the male T. Rex turns away from the female, he doesn't cast a shadow on a small patch of vegetation, only around it.
What looks like a small rock moves seemingly by itself without anything touching it in one shot as the Anatotitan drink prior to the Tyrannosaurus' attack.
The Dromaeosaurus shouldn't appear in this episode, as it was already extinct by the time it takes places. Although the animal in the series was never referred to by a proper name (it was perhaps meant to represent a "generic" dromaeosaur), the website later indeed identified it as a Dromaeosaurus.
The "crocodile" in the water is supposedly a Deniosuchus (according to the book), but Deinosuchis has already gone extinct close to 10 million years before this episode takes place.
The episode ends with time fast-forwarding from the Cretaceous period to a modern day landscape. When we start, we are in ancient North America, but as we arrive on modern Earth, we are suddenly on an African savanna.