Originally intended to be a comedic but more adult-oriented and silent animated show with no narration, until the Discovery Channel changed the format to a television documentary in the final stage of development. Hence the drastic shifts in tone, from scientific and serious to over-the-top sensational and goofy, as well as the tacked-on narration and the talking heads.
Twelve hour-long episodes were planned at the beginning of production. The finished series cut this down to a mere four, thus many planned and storyboarded stories had to be deleted. According to some of the creators, only those stories "survived" that had been already close to being completed. However director David Krentz denied this, claiming that the finished segments were chosen based on story quality.
After the televised version of the show had met with mixed viewer reactions, the Discovery Channel decided to postpone releasing the DVD and Blu-ray, and began working on a drastic re-cut, to present the series as it was originally conceived. They eventually released a theatrical movie in the form of Dinotasia (2012) with Werner Herzog as the new narrator, although the original series had to be cut down for time, and some segments didn't make it into the film.
Several different animation teams worked on the special effects for the program, which lead to stark shifts in animation quality. Episode one and much of episode three received very low-quality effects and error-filled animation, while episodes two and four, as well as certain parts of episode three contain much better crafted imagery with more realistic and convincing animation.
The reason why the large dicynodont Ischigualastia from the first episode looks like the tusked Placerias (a creature made famous by another paleo-documentary, Sur la terre des dinosaures (1999)) is that originally, they planned the segment to take place in prehistoric Arizona rather than South America, and thus created animation models based on Placerias. When the setting was changed, there was no time left to redo the model, and so the Ischigualastia received tusks for the episode, although the actual animal lacked them. Strangely, the presence of tusks still remained a plot-point in the story.