If MTV’s The Jersey Shore was remade into a feature-length film and given a darkly humorous treatment, you’d have Don Jon. In the role of Jon (dubbed “the Don” by his friends for his sexual prowess), Joseph Gordon-Levitt has shed the remnants of his innocent, boy-next-door charm; with his gelled hair and a life that consists almost solely of hitting the gym and going to clubs with the goal of bedding gorgeous women, he’s a perfect stand-in for the Shore’s Situation.

But Jon’s one true passion? Porn, which he claims beats out “real pussy” every time. The self-styled Lothario rhapsodizes crassly on the subject, comparing the quality of the “tits,” “ass,” and “blow jobs” of simulated sex vs. real life (demonstrated through the inclusion of actual porn clips) in a dead-eyed voice-over narration that almost evokes Edward Norton’s bleak musings on the banality of modern life in Fight Club. Jon is much less self-aware, but the emptiness of his own existence is made clear to the audience in a hilariously and intentionally heavy-handed fashion: a series of scenes takes Jon from the gym to the club to church to family dinners with little variation. Director and writer Gordon-Levitt clearly revels in taking blows at the monotonous Guido lifestyle: Jon rotely recites Hail Marys as atonement for his sins as he pumps iron, while moments of Jon en famille are enlivened by his lecherous, wife beater-clad father (Tony Danza).

Soon Jon meets the apex of perfection (or, in his parlance, a “dime,” or a 10): Barbara Sugarman, the comely, if high-maintenance, Scarlett Johansson, clad in a Bebe-heavy wardrobe that Sopranos moll Adriana La Cerva might have considered high class (and with the appropriate Jersey girl accent to boot). Barbara sets about trying to better Jon: she puts the kibosh on his porn habit and, eager to see her boyfriend leave his bartendering days behind him, sends him to night school. There, he sneaks illicit glances of pornographic movies on his smartphone and meets the quirky but emotionally fragile Esther (Julianne Moore). After the relationship with Barbara fizzles (yes, Jon just can’t quite quit porn), Esther helps him realize what the audience already knows—how self-centered and meaningless his attitude toward sexuality has been—and how to change.

Chock-full of visual sight gags (Jon’s claim that his breakup with Barbara has freed him is followed by a time-lapse montage of him spending some one-on-one time with his laptop; Barbara’s own unrealistic view of relationships is driven home by a shot of a Titanic movie poster in her childhood bedroom), the film is at its best when it turns its scrutinizing lens on its characters, mockingly dissecting their flaws. However, Don Jon is fairly light on plot, and the story does drag in places—while the jokes are clever, their charm eventually wears.

The shift from caustic and derisive to genuine and heartfelt, as Jon divorces himself from porn and begins a real connection with Esther, is also a bit discordant. Although the narrative feels rushed, Moore and Gordon-Levitt convincingly convey authentic emotion. The flashes of vulnerability crossing Gordon-Levitt’s manufactured persona of the “Don” as he develops real feelings for Esther are particularly powerful. Despite the issues with pacing and the abrupt change in tone, this is an energetic and original take on the concept of the “unexamined life” that will leave audiences eager for more from this debut director.