Starring Woody Harrelson and Kat Dennings. Rated PG. Opens Friday, February 19, at the Cinemark Tinseltown

Tina Turner may think we don’t need another hero, but Arthur Poppington doesn’t agree. A somewhat-less-than-ordinary schmo in an unnamed modern city (Toronto, in fact), Arthur decides that something has to be done about the bad behaviour all around him. He has no special powers, no family, and a low IQ, but he decides that the time is right for a superhero called Defendor—and don’t you dare spell that wrong. Fortunately, he has a nifty hideaway, some greasepaint, a few good industrial tools (plus some angry wasps), and, best of all, is played by Woody Harrelson.

The versatile actor (who dons a much different uniform in The Messenger, an Iraq War–related drama opening here later this month) is the principal reason to see Defendor, an engaging social satire that doesn’t quite pay off. It’s a first feature for writer-director (and actor) Peter Stebbings, and he certainly makes the most of a small budget and his obvious rapport with the on-screen talent.

I’m not convinced that the central framing device, with orange-suited Arthur being interviewed by a court-appointed psychologist (Sandra Oh), was the best way to get at Arthur’s troubled back story. Apparently, he was deserted by his drug-addled mother, and this lends resonance to his growing affection for a crack-puffing streetwalker played by Kat Dennings (Nick and Norah’s Infinite Playlist) and, for some reason, called Kat. She leads Defendor to a crooked cop (Elias Koteas), perhaps enabling him to find the mythical Captain Industry he blames for his mother’s demise.

All the actors work hard, but they can’t quite escape the one-dimensional nature of their conceptions, and the tale fizzles toward the end. It’s worth mentioning that Michael Kelly, as Arthur’s only loyal friend, manages to convey some realistic emotion without any heroics at all.