Time Out says
According to jailbird movies---recent ones, at least---getting sent to the slammer equals gaining entry to a finishing school for self-fulfillment. Prison is no longer just a place where petty thieves can work their way up the power structure if they use Machiavellian cunning and contraband-accommodating orifices; per Bronson, A Prophet et al., it's the cocoon where cons morph from caterpillars to perfectly realized criminal butterflies. Danish directors Tobias Lindholm and Michael Noer's take on the genre initially heads down the perp walk most traveled, albeit with a more ominously droning soundtrack and green-brown cinematography that's grimier than your average behind-bars drama. Introduced to R's fresh fish of a hero, Rune (Asbk), we watch the newbie learn the law of the concrete jungle: "You either fuck someone up," he's told by a vengeful inmate, "or you get fucked up!"
Rune does what he's told (there go a stoolie's teeth), then figures out how to move a bigwig's narcotics; soon enough, he's enjoying a better view of the yard. That's the moment that the movie starts to switch tracks, gradually moving its focus to Rashid (Al-Jabouri), Rune's Arabic cohort---and when the film's brilliance starts to surpass its brutality. Both characters will follow similar arcs, as this unflinching parable brings the hammer down on its cinematic brethren's fetishization of cell-block Rockefellers. R's final shot says it all: The house wins. The house always wins.