The program received much criticism for presenting theories as solid facts. The creators argued that while they were making a documentary, their goal was also to entertain, and since the theories about these prehistoric creatures always change, they couldn't possibly have made a TV show that accurately depicts what the world of the dinosaurs may have been like. And they were right - many theories presented in the show have by now been declared outdated and incorrect.
Mike Milne from Framestore originally declined the request to produce CGI animation for the series, but after having thought through the possibilities, he finally offered to help out. It turned out to be a wise decision, and the series was a smash hit.
Early animation tests made for the series contained computer generated reconstructions of the carnivore Eustreptospondylus, the long-necked Cetiosaurus (with an incorrectly positioned neck), a flock of flying Rhamphorhynchus and a beached Liopleurodon (whose tail was a physical prop operated by Tim Haines). Of these, only the Cetiosaurus didn't get to be featured in the finished series.
The success of the series not only lead to several sequels and imitations, but also gave rise to various other, part scientific-part fictional television shows and movies. These use compelling narrative and often movie-quality special effects to entertain and educate viewers.