These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
They Just Didn't Care: in regards to actually adapting the novel, they obviously didn't. Besides the premise of reviving dinosaurs by modifying chicken cells, the only thing the movie has in common with the novel is the first name of a major villain.
YMMV Tropes for the book:
Genius Bonus: The novel discusses atavistic fear a few times. The conceit being that because primitive mammals learned to stay away from giant reptiles, the smells and sounds they make reawaken survival instincts in humans. Similar theories are put forth in Real Life about why nails on a chalk board or sirens causes unease (i.e. that they sound like the calls of predators that hunted our ancestors while they were still small.)
Jerkass Woobie: You eventually get to feeling sorry for Jane Penward, despite her many character flaws.
Older Than They Think: This book had some key elements that Jurassic Park would later bring to the public conciousness several years before it came out. Namely, dinosaurs are portrayed as bird-like, quick, and intelligent instead of lumbering cold blooded brutes.