For people whose primary awareness of novelist Chuck Palahniuk’s work comes from Fight Club (the movie version), Clark Gregg’s adaptation of Palahniuk’s Choke may come as something of a disappointment. Although it shares many thematic similarities with David Fincher’s cult classic, Choke has neither the dark thrills nor the visual stylishness of Fight Club, and comes off as a fairly lighthearted and even optimistic lark despite some very sordid plot developments. Fans of kinky sex, weird urban legends and mild blasphemy will get their fill, but underneath all that seediness is a story that turns out to be rather heartwarming and sweet.

Like Fight Club, Choke focuses on a neurotic guy who has some seriously odd hobbies: Victor (Sam Rockwell) works as a historical re-enactor in a colonial township, makes money by pretending to choke in restaurants and then mooching off his “saviors” and regularly attends sex-addiction meetings (unlike the protagonist of Fight Club, though, he actually does suffer from the problem the meetings are meant to address). He also tries his best to care for his ungrateful mother (Anjelica Huston), who is slowly succumbing to dementia in a mental-health facility.

It’s there that Victor meets Paige (Kelly Macdonald), a doctor who becomes the first woman he’s ever fallen in love with (and thus, of course, the only one he can’t perform with sexually) and starts to turn his life upside down. Other odd detours include Victor thinking he might be the half-clone of Jesus Christ and ending up with a certain sex toy lodged somewhere unpleasant for the movie’s last 20 minutes or so.

Gregg (who also adapted the novel and plays a supporting role) treats all of these sordid developments with a light touch, and he certainly has none of Fincher’s panache when it comes to shot composition. But this is a more low-key story than Fight Club, and it works best when the potentially unsettling elements are presented in a straightforward manner. And the romance between Victor and Paige, while certainly offbeat, has a warmth to it that belies all of the film’s outward cynicism.

Rockwell does a good job of keeping Victor grounded even as he engages in increasingly unhinged acts, and he and Macdonald have a nice chemistry. The movie is never quite as transgressive as it appears at first to be (or as Palahniuk’s reputation might suggest), but its ultimate message is both universal and a bit radical: Scam-artist sex addicts and mentally unstable stem-cell advocates fall in love just like everyone else.