I don't care what others say, this movie is a true JP sequel, I know it's not as good as the first for some flaws and reasons, one of those reasons is that because the movie was completely different from the novel but we need to understand some problems that caused the final product became what we got.
1st problem: The novel has been released exactly when the film was already in production stage in 1995, the movie even was not supposed to be The Lost World, the sequel was meant to be titled Jurassic Park 2 because Steven Spielberg and David Koepp had written their own stories that had nothing to do with novel.
2nd problem: As the book has been released and JP fans were not expecting to get a loosely adaptation of it, Spielberg and Koepp tried to make a movie mixed by their ideas and Michael Crichton's story which was more closer to what fans would like.
3rd problem: One decision changed everything, Spielberg wanted to make even the third sequel which its story would be around a Trex rampage over the mainland. Yes, the original ending of the second movie was supposed to be a part of the third movie but unfortunately JP first sequel production tired and disappointed him, just imagine working with many full size dinosaur animatronics which they are even more than what they were in the first film and he would had to do this again for third one, so he changed the story again by adding his last ideas which he wanted to be produced and finished his directing career with the franchise, I'm pretty sure his painful memories and experiences on Jaws with those terrible shark animatronics was not effectless on this decision.