Science Marches On: Travis mentions that some dinosaurs have two brains: besides the regular one, apparently they had another one farther down the spinal cord, near the hips, which isn't true; it was based on an old theory based on the wide holes in those dinosaurs' hip vertebrae—bigger, in some cases, than the brain case. In reality, most terrestrial vertebrates' spinal cords are thicker where more motor control is needed, like with using large limbs, such as hindlimbs. The confusion is compounded in some dinosaur fossils because nerves might not be the only thing filling up the holes in their spines. One theory is that it could've been filled with another organ called a "glycogen body", which birds (dino descendants) today have, but it's still very unclear what that organ does.
The date to which the safari expedition travels is given as roughly 60 million years BC. Judging by modern radiometric dating methods (which were less developed at the time the story was written), this date should've taken Eckels to the middle Paleocene rather than the late Cretaceous, and as such his T. rex quarry should already be 5-6 million years extinct.
Not to mention how the oldest known butterfly fossil doesn't crop up until 55 million years ago. For the butterfly-lineage-wipeout phenomenon to work, Eckels would've had to step on a moth.
The Shelf of Movie Languishment: Completed in 2002, but delayed for three years due to flooding in Prague where the film was shot, as well as Franchise Pictures going bankrupt.
Troubled Production: Extremely. The film was effectively released unfinished, and it shows in things like the cheap and very obvious CGI.
