Grade: C

From the title on down, simplicity is the hallmark of this little movie by the Duplass Brothers, among the most notable practitioners of the stripped-down, improvisational style that’s come to be called “mumblecore.” The latter part of “Baghead” is a sort of minimalist horror movie in which the supposedly terrifying villain is nothing more than a guy wearing a brown paper bag on his head. It’s probably the least specific vision of a threat in a scary picture since the witch you didn’t see in the Blair woods.

Of course, it’s also half a joke, a riff on the absurdity of the horror genre as well as an example of it. And it’s only the second half of the picture, which starts out as an affectionate satire of the underground movie scene and relationship comedy-drama before segueing into the baggy stuff.

Those initial reels are, in fact, the best part of this very uneven super-low-budget exercise. The scenes of the screening of an ersatz “mumblecore”-ish flick at a grubby little festival—including a spot-on parody of a Q&A afterward—will be priceless to those personally acquainted with such tacky events. And the cell-phone subterfuge the central quartet—couples Matt (Ross Patridge) and Catherine (Elise Muller), Chad (Steve Zissis) and Michelle (Greta Gerwig)—use to sneak into the after-party has the ring of absurd honesty to it. The ensuing sequences showing the shifting emotional currents among the four are also interesting, the largely improvised, overlapping dialogue coming across as realistic and the glances and halting come-ons caught by the camera having a ring of truth, too.

But there are definite drawbacks to the method as well. The acting across the board is pretty amateurish, and the camerawork is understandably ragged, with only the most cursory sense of composition. Mumblecore product is frequently dismissed as nothing more than glorified home movies, and “Baghead” could serve as confirmation of the charge.

The most unfortunate part of the picture, though, is the turn to genre business in the last act. All the stuff about the shrouded villain stalking the two couples at the isolated cabin where they’ve gone to write a screenplay is frankly weak, and indifferently played out, with far too many murky, unfocused shots of the quartet running through the woods. Quite simply, it works neither as a real horror movie nor as a take-off on one. There’s an attempt to recover with a cynical concluding twist, but it’s a lot less clever than the makers apparently think.

So “Baghead” will hold a certain intrinsic interest for students of the moviemaking fringe as an example of America’s radically undogmatic variant of the no-frills Dutch Dogma movement, but taken on its own, it’s the sort of thing that’s usually referred to as “showing promise.”