For every thriller like The Usual Suspects or The Crying Game -- movies that contain twists so sudden, so shocking and so unexpected, we can't help but radiate appreciation at their ability to catch us offguard -- we can always expect to stay one step ahead of the game with movies like Novocaine and Heist, two snaky new pieces that never quite manage to pull the wool completely over our eyes. Maybe it's because audiences are becoming more cinema-savvy, or maybe it's because movie scripts are becoming more sloppy -- whatever the reason, it's getting harder for crime flicks to get the drop on the collective gullibility of contemporary filmgoers (lately, it's been fantasy films like The Others and The Sixth Sense that have done a better job at turning our heads 360 degrees).

Of this pair of new releases, Novocaine at least has the ability to fool some of the people some of the time. Co-written and directed by relative newcomer David Atkins, this oddball effort -- a neo-film-noir-cum-black-comedy -- benefits primarily from the casting of Steve Martin as the hapless hero. He's a dentist whose thriving practice and picture-perfect romance with his perky, brainy assistant (Laura Dern) are both jeopardized by his instant infatuation with a new patient, a disheveled dope addict (Helena Bonham Carter) whose mere presence gets him tangled up in the usual blackmail-and-murder scheme.

Martin brings his offhanded comedic manner to a well-worn character type, and in doing so gives the film a fresh coat that suits it nicely. Still, did his character have to be so thick? Noir and neo-noir protagonists usually aren't the brightest guys around, but Atkins seems to go out of his way to make this dentist a particularly IQ-deprived clod. And while there's one ninth-inning twist that managed to catch me off guard, most of this follows familiar patterns that become both more obvious and more contrived as the piece unfolds. Atkins may have thought he was making a steel mousetrap of a movie, but the end result is more like a rickety house of cards.

Despite its flaws, though, Novocaine is preferable to Heist, which competes with last summer's DeNiro-Brando debacle The Score as the most disappointing caper yarn of the year. David Mamet wrote and directed the film, which means the dialogue includes such attention-grabbing mouthfuls as "I'll be as quiet as an ant pissing on cotton" and "My motherfucker's so cool, when he goes to sleep, sheep count him." And the cast is headed by the Get Shorty trio of Gene Hackman, Delroy Lindo and Danny DeVito, which means good performances won't be in short order. But for a movie that's obsessed with double-crosses, triple-crosses and even a couple of right-crosses, this is ultimately about as easy to patch together as a six-piece puzzle. The actual heists depicted in the film consume far too much screen time (watching guys smash open jewel cases gets dull reeeal quick). Even without having read the script, we know as much as the actors do about how this yarn about a seasoned thief (Hackman) pulling off One Last Job will unfold -- right down to the fate of the gang member with the lowest billing (Mamet regular Ricky Jay), the loyalty of Hackman's significant other (Mamet's miscast wife Rebecca Pidgeon), and even the climactic switcheroo.

Based on The Spanish Prisoner and now Heist, it's clear that Mamet needs to stay away from this sort of twist-laden tale. There are apparently no limits to this Pulitzer Prize winner's talents, and much of his recent work bears this out: The topical comedy Wag the Dog was a modest box office hit, the British period piece The Winslow Boy was a delightful change of pace, and last year's Hollywood satire State and Main earned a spot on my "10 Best" list. But when it comes to movies like Prisoner and Heist, we're now familiar enough with the rhythms to emerge way ahead of the game. With Heist, Mamet may have thought he was pulling a fast one, but the only person he ended up outsmarting was himself.