By the time it reached its fourth installment in 1987, the Jaws franchise was basically a joke, but in 1978 it was still pretty respectable, coming off of Steven Spielberg's acclaimed and hugely successful 1975 original. Spielberg even briefly considered returning to direct the sequel, although that duty eventually fell to Jeannot Szwarc, who came in to replace original director John D. Hancock. Despite a lot of production troubles, including Hancock's firing, numerous rewrites and Roy Scheider's apparent reluctance to star in the movie (which he did only out of a contractual obligation), Jaws 2 ended up about as good as you could expect such a redundant sequel to be. It's repetitive and unnecessary, but it's not entirely bad. Shark-attack movies have been living in the shadow of Jaws since 1975, and the same is true for Jaws 2.
It also rehashes the plot of Jaws in many ways, with a giant great white shark terrorizing the resort town of Amity Island, and the town's chief of police, Martin Brody (Scheider), sounding the oft-ignored alarm. Once again local officials refuse to take the threat seriously, and once again Brody has to take it upon himself to defeat the shark. That redundancy reduces the suspense, and you can sense a bit of Scheider's annoyance in his performance, although he does convey Brody's desperation at being stuck in the same damn situation all over again. Szwarc, too, is stuck in a no-win situation when it comes to the shark, since he can't really hold off on showing it the way Spielberg did (everyone in the audience knows what it looks like by now), but the more he does show it, the sillier it appears. Szwarc opts to give the shark plenty of screen time, as well as a badass scar from attacking a boat early in the movie, and it's certainly more of a proactive, vengeful villain (which of course makes no sense). There's a brief reference to the possibility of the original shark having somehow communicated with the new shark, which is quickly dismissed, but this one clearly has it out for the residents of Amity Island.
In addition to Brody and his wife (Lorraine Gary, also returning from the original), Jaws 2 spends a lot of time focused on a group of interchangeable teenagers, including Brody's son Mike, who serve as shark fodder. In its emphasis on teen antics and peril, Jaws 2 sort of resembles a slasher film, right down to the teens who get attacked just after deciding to have sex. The slasher aspect could have been a fun angle, but it isn't fully developed, and it has to share time with Brody's brooding and the self-serving maneuvers of the town leaders. For the first half of the movie, in which Brody grows increasingly paranoid about attacks that he attributes to the shark without conclusive evidence, I was imagining a more offbeat take that would have involved no shark attacks at all, just Brody going increasingly insane as he insists that a shark is terrorizing the town, except it's all in his mind.
Sadly, this is just a by-the-number shark-attack movie instead, although the climax, which puts Brody's kids in peril, is sort of exciting, and Szwarc and the various screenwriters at least find a new and interesting way to kill the shark that doesn't duplicate the ending of the first movie. Given that this mediocre film is regarded as the best of the Jaws sequels, it's probably better for me to stop here and not move on to the later installments.