Debating the merits of Piranha 3D, director Alexandre (Mirrors) Aja's testosterone-driven valentine to Joe Dante's 1978 original and the excesses of '80s genre films in general, is a fool's errand; it is, after all, a movie about prehistoric fish preying on hormonal partygoers in various states of undress--and in 3D, mind you--so any review must answer the question--does it deliver what its key audience (young men, ages 14 to 24) require? On that front, the answer is an unequivocal yes. Special effects creators Greg Nicotero and Howard Berger present a veritable buffet of gruesome ways for the thinly drawn characters to die, from a piranha burrowing through a swimmer's head to the horrible encounter between a boat propeller and a longhaired victim. The sheer amount of nudity on display rivals a week's worth of Cinemax late-night screenings, rendered all the most excessive in 3D; as for the gimmick itself, it lends some unsettling depth to the underwater attacks. In short, if one attends Piranha 3D for grindhouse-style yucks, it's bound to be a rollicking good time. All others may find its relentless, Red Bull drive wearing; the whole affair is clearly meant to be a goof, just as Dante's original (produced by Roger Corman and penned by John Sayles) was, but where Dante's target was monster movie camp of the '50s and '60s (as well as Jaws), Aja and writers Peter Goldfinger and Josh Stolberg take aim at either cynical zeitgeist elements like the Girls Gone Wild series (with Jerry O'Connell striking the right tone as its craven creator) or hapless partygoers, which leaves an unpleasant aftertaste of misanthropy. Where the film does succeed is in its supporting cast, which strikes the same winning tone as Dante's version; Richard Dreyfuss and Christopher Lloyd poke fun at their Jaws and Back to the Future roles, while Adam Scott, comic Paul Scheer, and Eli Roth give appropriately broad turns. Elizabeth Shue, of all people, is the sheriff hero and acquires herself well to the absurd story line, as do Steven R. McQueen (yes, Steve's grandson) and Gossip Girl's Jessica Szohr as the film's Young Lovers. Again, taking issue with Piranha 3D is like finding fault with a cheeseburger for being greasy, but for those expecting a full-course meal, the fish get all the big bites here.