Don’t let people tell you the ads for “Identity” - which depict a group of strangers, stranded by a vicious flood at a motel where Agatha Christie’s systematic “Ten Little Indians” formula kicks into gear - are misleading. “Identity” is just that movie - until the final 20 minutes, when it becomes something more.

The twist of “Identity” seems to have already polarized those who have seen the film. Some say it elevates an otherwise routine horror movie to a surprising and satisfying realm of the psychological. Others dismiss it as ridiculous, saying the surprise revelation squanders the mood and mystery in favor of something silly and cerebral. As one of those wild 180 degree turnabouts that forces you to reevaluate everything you have just seen, it may be difficult for most viewers to predict (although I kinda did). While neither the slasher angle nor the psychological loop-de-loops that dominate the film’s final third are fully realized by director James Mangold and screenwriter Michael Cooney, “Identity” still emerges as a highly interesting genre bi-product - eerily intriguing and cleverly assembled, and worthy of much drive home discussion after that haunting final frame.

Among the new occupants of the aforementioned roadside motel are a limo driver (John Cusack) transporting a washed-up actress (Rebecca DeMornay), a stepfather in crisis (John C. McGinley), a corrections officer (Ray Liotta) with a passenger who happens to be a serial killer (Jake Busey), a hooker with a heart of gold (Amanda Peet) and a pair of young newlyweds (Clea DuVall and William Lee Scott). Both the phones and the roads are out. And, of course, people start to die. While Cusack and Liotta search for a murderer (aside from the obvious one) among their little group, Mangold cuts to a second story thread about a man awaiting execution (Pruitt Taylor Vince) and the psychiatrist (Alfred Molina) working his case. It’s best not to reveal much more. In fact, since you know there is a “twist”, you probably know too much as it is.

Director Mangold (“Cop Land”) has fun turning slasher movie conventions on their head, staging a classic “dark and stormy night” scenario with due attention to menacing atmosphere. The cast is strong, particularly John Cusack (who contributes wonderful nuances to a very different type of Cusack role), Amanda Peet, and John Hawkes as the likeable sleazebag motel manager. Unfortunately, having Jake Busey play a crazed convict hardly qualifies as risky casting (the man looks like a lunatic - could we be a little more creative, please?). As bodies pile up and a general feeling of “what the hell is going on?” takes hold with a spooky series of unexplained coincidences, Mangold achieves what few horror directors are capable of: turning the audience into trembling sleuths, anxious to unravel the ultimate mystery. When the carpet is pulled from under our feet, some will be dumbfounded and others intrigued. Put me in the latter category. For all of its preposterous calculation, the film gives you something to chew on and mull over for hours after viewing. And, what would you rather see? “Final Destination 3”?

“Identity” is a scary, crafty and original piece of hokum, complete with psychological trimming. Let’s put it this way: you will either like the film’s trippy leap of logic, or you won’t. Me? I liked it.