Everything in the movie, from the chomping shark attacks that churn up the splashing water with Hawaiian Punch foam to the way that a humungous great white meets her fate at the end, takes an obvious page from Steven Spielberg’s gambits and techniques. But shark movies, because of that derivative quality (and because the directors are not Spielberg), often tend to be dreary claustrophobic affairs. Whereas “Thrash” has a lively competence about it, and a touch of fluid originality in the staging.
