The original Piranha was a decent monster movie with some sly humor here and there. The remake was crass and vulgar but in a rather delightful way. The sequel is jut crass and vulgar. Worst of all it's lazy. It does nothing new and just apes the plot point of the first nearly beat for beat. When it adds something you can beat it was from some other film. It's like, "Hey remember Planet Terror? Let's give Ving shotgun legs!"
The plot involves a water park run by a sleazy corrupt step father of our final girl for this film. How sleazy is he? Well he's installed strippers instead of lifeguards and has a nude swimming pool armed with "Cootch Cams." He's also spreading graft and bribes around so he can secretly pump his own water and not be on the grid. Said water is of course filled with killer piranha and everything else works pretty much like you think it would.
The special effects are on par with the first film. They try to up the ante on the violence but scenes involving an unknowing three way between man, woman, and fish just wind up being ugly and not scary or darkly funny like in the first one. The cameos also are ham fistedly inserted into the film. Christopher Lloyd and Ving Rhamses manfully handle their woefully underwritten scenes. Gary Busey, though, just looks lost and David Hasselhoff was just sad. Admittedly, his role was suppose to be a sad role in that he was playing "himself" as a washed out overaged celebrity hasbeen, but there is no bite to his role to lift it up to something like comedy.
Look, it's no worse than most straight DVD horror films. But it disappoints because there was more money here, some decent actors and at least a pedigree of entertainment. Instead we get tired, lazy, and stupid writing supported by mostly lack luster acting. It's just sad.