Japan’s national insecurities are writ large in this gory, live-action adaptation of the phenomenally successful manga, which is being released theatrically in two parts. Following a huge bomb, humanity has walled itself in against man-eating giants called Titans. These grotesque, smiling cannibals have no sex organs – in fact, it’s hard not to see the scenario as a metaphor for extreme xenophobia, especially when the “reveal” is that Titans aren’t so inhuman after all.

At any rate, in a gruesomely inventive and terrifying sequence, the Titans break through the wall and begin snacking on people. Our hero, Eren, loses his girlfriend, Mikasa, in the feast. But two years later, when society has regrouped along vaguely fascist military lines, Mikasa reappears as the greatest Titan-slayer of them all. Too bad she’s dating someone else. Will Eren fight through his heartbreak, unleash the Titan within and finally lead his friends to the ocean? (Mikasa: “The big water you mentioned?”)

The actors are mostly self-conscious and dreadful, but their fringes are undeniably impressive, and the film has a schlocky B-movie appeal, propelled by terrific special effects and the can’t-look-away horror of watching a motley crew of giggling dim-witted zombies chew on people like jerky. The second half descends into a bit of a Godzilla meets Street Fighter slugfest, but you knew that already.