According to “Army of Thieves,” the art of safecracking simply comes down to listening. No matter the safe nor how intricate the model, an ear to its door while spinning the dial is the key to unlocking all of its treasures. Ear, door, voila! You’re in. 

There’s probably a little more to it than that, but “Army of Thieves” is unconcerned with those frivolous details. This lark of a heist movie — a spinoff/ prequel to this summer’s Zack Snyder-directed zombies-in-Vegas splatterfest “Army of the Dead” — is more into riffing on heist flicks and creating a tossed off mood of nonchalance than it is in getting down and dirty with specifics. It’s not willing to invest in its premise or its characters, so in turn, it’s difficult to invest in what it’s selling.  

What it’s selling is pure style. Matthias Schweighöfer, who also directs, is Ludwig Dieter, a safecracker extraordinaire who’s in it for the art of the steal. He deeply respects safe makers and the craft that goes into their creations, and he gets the opportunity to break into three vaults designed by the Picasso of the safe world. He’s all in.