Regardless of characters' theories, the film never unequivocally adopts a single explanation. In fact, the "wrap up" at the end is actually The Happening’s most direct tribute to Dawn of the Dead. This is not a categorical summation or pronouncement but an intentionally comic explication of the event by an “expert”... and the exasperated reaction by the show’s host. If you want to get the joke, watch Dawn of the Dead and pay close attention to the talking heads. But herein lies a problem. Should we really need to familiarize ourselves with a secondary film in order to "get" the equivocal nature of Shyamalan's ending? Not in a mass market movie! But we're getting ahead of ourselves. Let's back up a bit.

Like Romero in Night of the Living Dead, Shyamalan does do a reasonably good job with building up the sense of danger, from rumor to reality to panic to mass death and the potential for apocalypse. But he gets his film too tangled up in secondary mechanisms (not to mention other people's movies) to give his threat the immediacy it deserves.

In The Birds and the Dead movies, the threat is immediate and visceral. Birds or zombies attack. The characters defend themselves or die. In The Happening, the threat is more conceptual. Neurotoxins are released into the air by an unknown agency (the trees? the government?), and those infected kill themselves. (Technically, they lose their self-preservation instinct, and for some reason, this translates into an immediate and fatal burst of self-destruction).

Shyamalan did a nice job with the unseen threat in Signs. But there was always a physical bulk behind the invisibility, and that physical bulk could be fought. Here, the struggle is against something insubstantial (the wind) and microscopic (the neurotoxins it carries) and the destruction is ultimately carried out by a secondary agency (the infected individual against him or herself). This pestilence cannot be fought. All anyone can do is try to outrun it (or find an antidote!). And this makes the struggle seem less immediate, even passive.

By riffing off Hitchcock and Romero, Shyamalan creates certain expectations about the kind of threat his protagonists face and how they will fight it. Of course, Shyamalan lives to subvert expectations, but in order to do so successfully, he needs to create a work that at least nearly equals the ones he’s challenging. The expectations established by these films have, after all, seeped into our collective cinematic unconscious.

So does Shyamalan pull it off? The concept he’s dealing with has potential. In “nature gone wild,” the things we take most for granted are typically the things that turn against us. And what do we take more for granted than the air we breathe? (No matter the cause of the crisis, air is the common denominator here). The concept can work, but it will need strong characters to drive it and actors who will sell it.