The Ornitholestes in this episode produce a different sound than in the original series. The sounds used in this special are actually the high-pitched noises that the Dromaeosaur made. The other dinosaurs retained their original sound effects.
Big Al's foot injury switches from being on his right foot to his left in the closeup of his foot, near the end of the episode.
As the female Allosaurus roars at Al, she opens her mouth wide, but in the immediate following shot, her mouth is only slightly opened.
The CGI Diplodocus (correctly) has a single claw on each of its front feet, the other four digits ending in stumps lacking claws. But the physical Diplodocus prop has sharp claws on each of its fingers.
The feet of Al's carcass change position between shots.
The Dryosaurus is shown having a hallux (innermost toe). The real animal lacked this.
Big Al's skeleton is shown to be in the University of Wyoming Geology Museum. Even Big Al's "ghost" appears next to it in the follow-up "behind the scenes" special. But the skeleton put on display is actually a cast. Big Al's real fossils are kept in Montana.
The plates of the dead Stegosaurus noticeably bend sideways. Since they are made of bone, this is quite unrealistic.
The animation error in which the teeth of the Diplodocus "stretch" as they open their jaws got carried over to this spin-off from the original Walking with Dinosaurs (1999) series.
When Al is hit by the neck of the sick Diplodocus, the tip of his tail passes through the neck.
As Al swallows the lizard, its tail passes through his tongue.
When the female Allosaurus tackles Al to the ground and jumps over him, for a moment as a cloud of dust bursts up, she becomes transparent.
During the hunting scene on the salt planes, at around the 18:27 mark, the two Diplodocus tails on the left side of the screen are twisting in the exact same pattern, which in reality would be very unlikely.
When the Allosaurus roars at the left-behind Diplodocus, the texture of the Allosaurus' armpit is behaving oddly: there's a dark line jumping around on it.