Like a street-corner con daring rubes to bet on his shell game, writer-director David Twohy throws down a challenge to viewers in his suspense thriller "A Perfect Getaway": See if you can spot the killers -- and the victims. You'll probably lose your money if you take his dare. Which is not the same thing as seeing a good movie -- it's still a gimmicky, tricked-out tale that is all too self-aware. But the film does keep you guessing and probably guessing wrong.

The R-rated film should play well to young adults up for a little screenwriting intrigue mixed in with their movie intrigue. Marketing will play a big role as will word-of-mouth to give Universal a decent theatrical run.

Twohy tips his intentions early when two male characters get into an intense conversation about screenwriting. Cliff (Steve Zahn), a screenwriter whose first sold script is going into production, is on his honeymoon, backpacking along a remote trail on Hawaii's tropical island of Kauai with new wife Cydney (Milla Jovovich). They encounter another, much more athletic couple in Nick (Timothy Olyphant) and Gina (Kiele Sanchez). Nick, an Iraq War vet, has been to a screenwriting boot camp and is brimming with story ideas.

The discussion leads to Nick's theories about the "red snapper" -- by which he means the red herring writers toss into mystery/suspense movies to throw audiences off. So Twohy defies you to spot the red herrings and figure out what he's up to.

It seems another honeymoon couple was butchered on the island of Oahu. Now why this would logically threaten these couples is unclear, but it does. It really does. Oh, and another couple turns up looking like -- and Twohy actually references the film -- "Natural Born Killers." Kale (Chris Hemsworth) is a tattooed ex-con on parole, and Cleo (Marley Shelton) is his go-along-with-anything girlfriend.

Want more clues? Well, Nick is a teller of tall tales. He insists he survived a plane crash and later a fragmentary bomb in Iraq. "He's really hard to kill!" laughs Gina. She says this more than once. Other characters pop up here and there, all looking vaguely suspicious.

About two-thirds of the way through, Twohy, as threatened, throws a switch that slams all expectations sideways. It's not a bad plot twist, only the surprises pretty much end there, and the movie does not. The formulaic nature of the whole rigged affair now is revealed, and the third act plays out as you would anticipate, with credibility pretty much thrown off one of those Hawaiian cliffs.

The actors give themselves over to this elaborate game of Clue, except for Zahn. Hard to say what he's playing as he overdoes by half the meek, bespectacled writer afraid of his own shadow. Jovovich gives a fairly subtle performance as the other half of the honeymooners. Olyphant and Sanchez seem to have fun with their roles, and it shows in solid performances. Hemsworth and Shelton don't have much to do other than act menacing.

The movie's exotic scenery, shot mostly in Puerto Rico, is a plus.

Opens: Friday, Aug. 7 (Universal)