Although the show is called "Walking With Dinosaurs", only one type of dinosaur appears in this episode, not counting the preview for the next episode at the end.
The episode is infamous for vastly overestimating the size of Liopleurodon, stating it could grow up to 25 meters when no specimen larger than 6 m has ever been discovered. This size estimate most likely stems from various misinterpreted fossils and miscalculations that were publicized in the '90s. Based on very fragmentary and never properly identified fossils, assertions about the animal's proportions and spine length, as well as comparisons to related genera (like Kronosaurus), some scientists believed Liopleurodon could reach 12, 18, or even 20 m, with some arguing that large adults could grow up to 25. Later, a juvenile pliosaur found in 2002 (dubbed the "Monster of Aramberri"), was estimated to have grown to 15 m and thought to have been a Liopleurodon. These ideas and the erroneous science behind them are not supported anymore. Liopleurodon was most likely only 6 meters long.
The shots of the young Ophthalmosaurus chasing fish were taken from an older BBC documentary in which penguins chased fish. The penguins were simply erased from the shot and replaced with CG Ophthalmosaurus, ensuring realistic interaction with the fish.
The Eustreptospondylus animation is actually a modified Allosaurus animation with different colors and without the characteristic eyebrow ridges.
Many people would argue that the rise in Liopleurodon's popularity can be attributed to this episode's portrayal of the animal. For example, nearly all of the toys that came out after it had aired carried the same color scheme it had in the show.