Gangster Squad was originally scheduled to open in theaters on September 7, 2012. Then came the massacre at an Aurora, Colorado theater's midnight showing of The Dark Knight Rises, a showing that was preceded by Gangster Squad's trailer. The trailer, which featured a blink and miss shot of a theater shooting, was immediately pulled and then Gangster Squad was delayed to allow time for re-editing and reshoots.

The delay was just four months, but it makes a world of difference in what it says about the film. A September movie ushers in the fall movie season of serious dramas bound to be considered in year-end lists and Oscar races. That seemed fitting for a true crime drama set in mid-20th century Los Angeles and boasting a good deal of star power.

A January movie, on the other hand, is essentially moribund. Studios release movies in January as counterprogramming to the expanding awards bait and widely-seen big commercial Christmas Week openings. A January movie has no chance of competing for awards or cracking Top 10 lists. In recent years, the calendrical wasteland has typically been reserved for horror movies not screened for critics and expected to have toxic word of mouth. Very few movies have opened in January without a qualifying run the previous year and had any real artistic value.

That time alone would not be enough to clear Warner Bros.' conscience and that the studio would be okay with a January debut drains most of the promise that lied in this film's A-list cast, historical subject matter, and Zombieland director Ruben Fleischer.

In 1949, one criminal rules Los Angeles: the Jewish mobster Mickey Cohen (Sean Penn). Cohen has his hand in every racket and is ruthless when it comes in punishing those who let him down. He has everyone from the highest judges to senior police officials on his payroll and looking the other way, plus virtually all crime running through the West Coast goes through him.

One good police sergeant named John O'Mara (Josh Brolin) seeks to loosen Cohen's hold on his city. O'Mara experiences resistance when he takes drastic steps to bust some of Cohen's associates. But the LAPD's Chief Bill Parker (Nick Nolte) shares the distaste for Cohen and gives O'Mara his blessing to follow his heart and bring Cohen down.

O'Mara assembles a secret undercover unit whose name gives the film its title. His very pregnant wife (Mireille Enos) helps him pick the handful of trustworthy law enforcers on whom he can count. They include an African-American (Anthony Mackie) who takes bold actions to crack down on drug dealers, a sharpshooter (Robert Patrick) whose exploits have already become immortalized in comic books, his Hispanic tagalong (Michael Peña), and an intelligent family man (Giovanni Ribisi). Rounding out the squad is the suave, young Sgt. Jerry Wooters (Ryan Gosling), who has the audacity to secretly date Grace Faraday (Emma Stone), Cohen's new moll.

The gangster squad isn't afraid to play dirty, robbing from Cohen and threatening his income streams with actions designed to look like those of a rival gang. Cohen isn't reluctant to respond, though he is clearly facing his first real challenge in a long time.

Gangster Squad does a good job with nailing the period detail, even if such art direction begs for the use of film and not the less than state-of-the-art digital video. Despite the historical basis, the story does not sizzle any more than say the underwhelming Public Enemies did. Some aspects of the film compel (like the conflict between O'Mara's duties to his city and to his wife), while others (chiefly, Wooters and Grace's stealth romance) do not. The Gangster Squad itself has the feel of an Ocean's Eleven, with their scenes having a certain comic camaraderie.

The acting is a lot spottier than you would expect. Penn chomps on scenery, a performance that's reminiscent of a Dick Tracy villain and somehow also calls to mind his I Am Sam turn. Though he has his admirers, Penn proves here he's one of the weaker actors to have two Oscars to his name. Adopting a kind of wimpy voice with a hint of period authenticity, Gosling feels like he's acts down to suit the movie rather than to elevate to the high quality of his usual output. Brolin and the rest of the cast hit the notes they are expected to, but despite some nice efforts, you are never able to shake the feeling that you're watching a January movie, one whose timing and re-editing reflect the concerns of a studio not confident in its product.

Between 30 Minutes or Less and this, Fleischer shows he's only as good as his material. Few movies have material as strong as his debut, Zombieland. While Fleischer executed that to near perfection, he needs something better than what the first finished screenplay of ABC's "Castle" scribe Will Beall gives him to truly flourish. Gangster Squad has a lot of action and violence to justify its $75 million price tag. But the abundance of tommy gunfire and goon casualties cannot compensate for thinly-written characters and routine procedural devices (wiretaps, raids).

Amidst films like Texas Chainsaw 3D, A Haunted House, and The Last Stand, it's tempting to invoke the always humorous gag of declaring an early release the best movie of the year so far. But I'd be surprised if Gangster Squad hangs onto that shallow honor far into February.

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