A fame-hungry hothead boulders up to our hero Kick-Ass (Aaron Taylor-Johnson) and asks “how ‘bout a million hits on YouTube?” He starts swinging his fists while a companion films the altercation on a smartphone, hoping to capture something that collects more hits than Old Spice or the Star Wars Kid.

When our villain, self-assigned the no-frills moniker “Motherfucker” (Christopher Mintz-Plasse) robs a convenience store and discovers there aren’t any surveillance cameras recording him, his first response is to say “how is this supposed to go viral?”

Motherfucker joins Twitter (“he’s got like a thousand followers already”) and rises to fame. “I want to kill Kick Ass with my bare hands,” he says, all muahahahahaha, to himself. Then adds: “I’ve gotta tweet about this.”

When a ragtag group of heroes, outnumbered and outmaneuvered, need support, where do they go to spread the word? Their Facebook page.

Hollywood’s first social media superhero movie, Kick-Ass 2, has something to say about vacuous celebrity and online exhibitionism. It’s a great shame nobody — least of all director Jeff Wadlow — seems to know what that was or whether he ought to have bothered.

Wadlow’s sequel to 2010’s snazzy post-mod comic book pic is based in a world where vigilantism is synonymous with mental illness. It is similarly provocative, but the smug self-awareness of the original has lost its shockingly irreverent edge, displaced by a moral vacuousness that borders on the nihilistic.