The Ruins opened on Friday like most horror films, with a single, late Thursday night "promo" screening, to which the press was gamely invited in full knowledge that it would be too late for review, even for any reasonable web deadline. What's different about The Ruins is that it's not a remake or even a copy of any horror film of recent years. We're talking first-class material, adapted from a novel by Scott B. Smith, who wrote both the mesmerizing 1993 book A Simple Plan as well as Sam Raimi's masterful 1998 film of the same name. It's a terrific airplane novel, surprising and gripping, and Dreamworks could have made an outstanding film of it. But they threw it away, perhaps deliberately, hoping for some of that fast opening weekend green, and little caring about making something worthwhile or lasting (like A Simple Plan).