Let me get this out of the way right now: this is a bad movie. It's a very bad movie. But it at least falls into that "so bad, it's good" category. If there is not yet a Rifftrax of this movie, there should be. The title suggests that the film is a sequel to Piranha, though nothing about the story at all suggests this. It's no more a sequel than Home Alone 3.
The movie opens with a couple who are just reasonably attractive enough for cheap late-'70s porn deep-sea diving. They come upon a sunken ship, which they view as a perfect opportunity to... have sex. The girl suddenly appears having removed her bikini, then she grabs a big ol' knife they happened to be diving with and cuts her man's speedo off (I'm sure he was silently praying the knife wouldn't slip). So now the two almost-pretty people are nekkid under the sea and ready for some lovin' sea mammal style. But rather than just get to it, they take a moment to REMOVE THEIR BREATHING APPARATUSES! And so, as these two idiots are kissing underwater with what little air they have left, they are attacked by mutant fish. It's supposed to be scary, I guess, but it's not. Who even cares if the fish get them; these two morons are going to run out of air on their own any minute anyway. What this opening does do is reflect the standard '80s genre cliche that having sex will soon get you killed. Therefore, as an opening to a bad '80s horror movie, it's pretty expected and not the worst thing. The best part of the sequence is the water filling with red as the two are attacked and bleed out.
After the opening titles, the film has little more to do with what we saw in the tease. In a nutshell, the plot concerns a beach resort that holds a party every year when some native species of grunion spawns in it's ocean (that's the "spawning" of the title, which will never be referred to again). The people run down that night and get all the fish they can, and have a big fish fry. Only this year, instead of grunion, the beach is mobbed with mutant fish; some sort of pirahna or grunion species that the government has secretly cross-bred with flying fish to be a weapon. That's right: the government is using its resources to create weaponized fish. This is one step away from sharks with frickin' laser beams on their heads. Anyway, these fish have gotten loose or something and, after a few Jaws-like encounters where some swimmers are found dead, they attack the beach and kill a whole lot of people. So then our heroes swim down to the sunken ship where the fish apparently live and blow it up. That's the movie.
As is to be expected with a film of this nature, most of the characters are cardboard cliches with little to do other than to either move the plot along or to illicit an immediate audience reaction. There is a stodgy ship captain and his beautiful daughter who exists only so the young male character can kiss her, the boy's mother (who is of course seperated from his father) who uncovers the truth of the fiendish fish plot, and the minorities who get slaughtered. The actors who fill these roles are no better than the types they are playing. Several appearances from an older woman who spends her time flirting with a hunky resort employee are just embarrassing and do nothing for the film at all.
There's Mal, a stuttering nerd who is conned by two bikini-clad babes. Is this character supposed to be comic or not? Are we supposed to laugh at him? Because as things play out, we end up feeling bad for him. He's a cook who catches one of the girls stealing food from the kitchen for a party she's throwing. She says if he doesn't tell anybody, he can come to the party and get it on with her and her friend. Mal not only heartily agrees, but insists that he cook the whole meal and bring it with him. When he arrives at their boat, they take the food and then laugh as they pull away and let him jump in the water after him. I do not understand the purpose of this subplot. Is Mal just the comic relief? If so, the movie fails here, as the pathos tempers the humor. Or instead, is this supposed to be a way for the audience to hate these girls, and thus be glad when they finally eat it — sorry, are eaten — in the end? The latter seems to be more successful, but I question the movie's mean-spirited attitude toward the Mal character.
The plot begins moving when a diver is found dead and their bodies are taken back for examination. They have been killed by the evil piranhas or grunions or whatever they are. Then, when the body is lying there, a fish comes out from inside it and attacks one of the medical examiners! Fish continue to attack in strange ways. If I recall correctly, they seem to bite holes all over the victim, and then sit inside the body solely to jump out and attack someone later.
It's silly, but not nearly as silly as the epic climactic attack. While everyone waits eagerly for the spawning grunions so the fish fry can begin, the killer fish arrive and fly at their victims. The effects here are very poor, being noticeably fish puppets on sticks or wires. The sometimes attack perpendicular to the body, which is physically impossible. And when I say they fly, they don't just leap out of the ocean; they flap their enormous fins and buzz around like helicopters. The attack goes on... and on... and seems sillier with each passing second.
The one redeeming feature of this movie is Lance Henriksen, who plays the woman's husband. Unlike everyone else in the movie, he has a character, or at least Lance plays it like he does. Lance doesn't bother trying to play the reality of killer flying fish; instead, he hopes to keep his emotional focus on the woman he still loves. He never feels like a good actor slumming in a terrible movie. His performance lends the only real human element to an otherwise nonsensical picture, and Cameron so enjoyed working with Henriksen that it led to his being cast in several subsequent Cameron films. There is an everyman quality to the performance that reflects some of the same work Henriksen would do later on Millennium; no matter what the craziness is around him, he focuses his energy on the people his character loves. Millennium worked because Frank Black was not just out to fight demons and serial killers; he did everything to keep the darkness away from his wife and daughter. Henriksen brings a similar sensibility to this movie. Maybe it would have been different if his character had to fight off a flying piranha; he never does interact with the fish.
After the attack on the beach, the decision is made to plant a bomb inside the sunken ship and destroy all the fish. The movie never explains why the fish seem to live there, nor whatever becomes of all the fish on the beach from that night (and actually, why did the normal spawning grunions never show up?). This sequence is reasonably successful as our heroine swims through corridors trying to evade schools of mutant fishies. I must also credit this movie for doing something I have never seen before. I've seen a lot of bombs in a lot of movies. There's always a digital readout with a ticking clock. Why this clock exists, I don't know. But the bomb in this movie, though it has a clock, does NOT have a countdown. That is, the bomb doesn't go off when it reaches zero. Instead, it's just a timer with a normal running clock! They plant the bomb around 6:12 or so, and the bomb will go off at 6:30. It was so refreshing NOT to see a ticking countdown! It was a way for the audience to know how much time was left while avoiding the real cliché. The bomb is simply programmed to go off at a certain time.
Without Lance Henricksen, this movie would have no reason to exist. The horror elements are not scary, character threads don't all connect, and the effects are laughable. What would make the government want killer fish anyway? This is not a movie that James Cameron says very much about. And yet, without it, would Cameron have ever directed The Terminator? Would we ever have seen Lance Henricksen in Aliens? When all is said and done, Piranha Part Two is an oddity on Cameron's resume; a predictable low-grade movie that is no better or worse than can be expected.