"Smokin' Aces" is a frenetic, bullets-whizzing free-for-all that goes down like delectable junk food—at least during its first 90 minutes. As the expected climax comes into view, writer-director Joe Carnahan (2002's "Narc") makes several irreparable missteps that push the running time beyond its breaking point and pretty much ruin what has come before it. The crime actioner's inspirations aren't difficult to figure out—it's one-part Quentin Tarantino, one-part Robert Rodriguez, and one-part Guy Ritchie—and while it does a nice job of mimicking those filmmakers' slickly gritty style, it pales on a screenplay level. Overall, the dialogue is ho-hum and the characters unsympathetic, one-dimensional types. This would be okay if Carnahan hadn't stopped to look back, but a 180-degree switch in tone and a ridiculous last-minute "twist" botch the outcome.

When Las Vegas magician Buddy 'Aces' Israel (Jeremy Piven) agrees to testify against ailing mob boss Primo Sparazza (Joseph Ruskin), a $1-million dollar bounty is placed on his head for anyone able to kill him and snatch his heart. Israel skips town to hide out in the penthouse of a Lake Tahoe casino, but his whereabouts are quickly learned by a plethora of people itching for the loot. Before long, bail bondsman Jack Dupree (Ben Affleck), shamed ex-cop "Pistol" Pete Deeks (Peter Berg), female contract killers Georgia Sykes (Alicia Keys) and Sharice Watters (Taraji P. Henson), psychotic mercenaries Darwin (Chris Pine), Jeeves (Kevin Durand) and Lester Tremor (Maury Sterling), and many others cross paths as they set upon the casino. Hot on their trails are FBI agents Richard Messner (Ryan Reynolds) and Donald Carruthers (Ray Liotta), who catch wind of the plot while performing a stakeout on Primo's residence.

"Smokin' Aces" is less complicated than it wants to let on, spending close to a full half-hour to set up all the characters and explain in detail the plot before the setting moves to the Lake Tahoe casino where the real action takes place. Once the meat of the story gets underway with the abrupt deaths of some major players, the film kickstarts into overdrive. For the next hour, the pacing is rapid-fire quick, the over-the-top violence gleefully bloody, and the various schemes of each group of thugs and criminals cleverly entertaining. Writer-director Joe Carnahan throws everything but the kitchen sink into his lucidly-filmed, eager-to-please world of chaos, some of which work without serving a point—for example, the comic run-ins with a daffy grandmother (Marianne Muellerleile) and her karate-chopping, Ritalin-fueled grandson (Zach Cumer)—and others that wade too far into camp—i.e. cross-dressing lawyer Rip Reed (Jason Bateman).

The cast is huge, but this is no Robert Altman wannabe; the actors eat up their roles, but are handed little more than a quirk or two to shade them. Across the board, the characters are either caricaturized, despicable, underwritten, or all of the above. For what has the realism of a comic book, that is acceptable, but it doesn't aid in allowing the viewer to care what happens to any of them. The closest that someone comes to receiving multiple layers to work with is Jeremy Piven (2004's "Chasing Liberty"), dynamite as human target Buddy 'Aces' Israel. Israel life is closing in on him—he's a coked-out druggie suffering from regret, fear and depression, and it's all about to get a whole lot worse—and Piven gives the part his all as he delves into some pretty dark emotional corners. As sexy contract killers Georgia and Sharice, singer Alicia Keys and Taraji P. Henson (2006's "Something New") are spunky bright spots. And as straight-and-narrow FBI agent Richard Messner, Ryan Reynolds (2005's "Just Friends") exposes an adult intensity he has scarcely shown before.

"Smokin' Aces" is captivating from a swirlingly visual point-of-view, and director Joe Carnahan shows a maliciously humorous side that works well—in one scene, a fresh corpse is used as a puppet by the unhinged Darwin. There is a certain place in the finale where, had things promptly wrapped up, the picture would have went out on a high note. Regrettably, this does not happen, and Carnahan sees fit to turn deadly serious as he introduces a preposterous plot development that is totally uncalled for. The blackly comic fun stops dead in its tracks, and the movie finally culminates in a misbegotten, sobering whimper. When "Smokin' Aces" wants only to broadly please with an onslaught of cat-and-mouse destruction and gunplay, there is, indeed, a sick enjoyment to be had. When it delusionally strives to be more than this without earning the right, the film ends up shooting itself in the foot.