Gangster Squad is a gang war drama built on Western conventions, a rootin' tootin', Camel-smokin', whiskey swillin' shoot'em up.
—Roger Moore Movie Nation
The best thing about Gangster Squad is how they got the 1940s accoutrements right.
—Rex Reed New York Observer
The cops play things as dirty as the crooks in Gangster Squad, an impressively pulpy underworld-plunger that embellishes on a 1949 showdown between a dedicated team of LAPD officers and Mob-connected Mickey Cohen (Sean Penn) for control of the city.
—Peter Debruge Variety
Penn's over-the-top tirades and bullying threats are still there - it's a wild and woolly performance that isn't always as menacing as perhaps the actor intended it to be.
—Steven Rea Philadelphia Inquirer
Made up of synthetics rather than whole cloth, this lurid concoction superficially gets by thanks to a strong cast and jazzy period detail, but its cartoonish contrivances fail to convince and lack any of the depth, feeling or atmosphere of genre stand-bearers like "L.A. Confidential."
—Todd McCarthy Hollywood Reporter
Gangster Squad provides a welcome burst of heat and color, even if those qualities are more illusory than real and subject to a fast fade.
—James Berardinelli Reel Views
To be fair, this tawdry dose of pulp fiction ("inspired by real events") is not a complete waste of time. It offers the marginal pleasure of an all-star cast slumming their way through a thicket of routine plotting, almost laughable dialogue and the constant blaze of tommy guns.
—Roger Ebert Chicago Sun Times
In the last five minutes the film shifts gears and offers a tribute to law enforcement. But this tacked-on resolution is as sticky and fake as Sean Penn's make-up job.
—Claudia Puig USA Today
The soul of the era is missing, and with it any reason to care. In Fleischer's hands, the high-stakes shootouts are as stylish as a GQ spread, but it's nearly impossible to figure out who's zoomin' who.
—Betsy Sharkey Los Angeles Times
His (Fleischer) first feature, "Zombieland," was a half-witty genre parody. This one might be described as genre zombie-ism: the hysterical, brainless animation of dead clichés reduced to purposeless, compulsive killing. Too self-serious to succeed as pastiche, it has no reason for being beyond the parasitic urge to feed on the memories of other, better movies.
—A.O. Scott New York Times