In my opinion the departures from the Jurassic Park novel were not just incidental. I enjoyed very much the Jurassic Park visual effects, but I despised the script as one of the most disappointing adaptations of novels, because it completely failed to convey the message of the book. The central idea of the book was that there are things so complex, i.e. chaotic systems, that regardless how good you are and how great are your efforts to control them, unpredictable failure is unavoidable. I did not see anything of that in the movie, where the failure of the park was just the consequence of stupid mistakes made by a bunch of morons, not the consequence of objective laws, as in the book.