Tacky and intermittently entertaining is all"Piranha 3DD"sets out to be, and that is all this playfully graphic horror-comedy sequel accomplishes.

The first half of the film merely treads water in anticipation for the eventual bloodbath, and once the teeth start gnawing, it's just one laborious machination after another to get to the end of the movie, which stops without much of a resolution.

With most of the running time devoted to setting up and over-explaining the premise, mayhem gets short shrift.

The previous film was surprisingly delightful, with those successes being totally absent from this follow-up.