The Lost World: Jurassic Park

Skippable, and it contains the second-best sequence in the series. Those two facts coexist because the film around that sequence has nothing to say.

The sequence is the trailers over the cliff. Two vehicles are pushed slowly over an edge by a pair of adult T. rexes, and the film then spends several minutes with people standing on a sheet of safety glass that is cracking under them, one line at a time. It is engineered with the same patience as the kitchen scene in the first film and it is the last time this franchise showed that kind of discipline.

Everything else is a second trip to an island with a worse reason for being there. Spielberg has been fairly open that he was not engaged by it, and it shows in a film that is meaner than the original without being more serious: a safari of hunters arrives to capture animals for a park, a group of activists arrives to stop them, and the film kills a great many of both in ways designed to be enjoyed. The child acrobat sequence is the one most people name as the low point.

Then it goes to San Diego for twenty minutes, in a self-aware King Kong pastiche that belongs to a different film entirely. Nothing later needs any of this. Watch it for the trailer sequence and treat the rest as optional.