Like so many critics, pundits, skeptics and everyday viewers, my first impulse on hearing of Paul Greengrass' "United 93" was to skeptically view it as a possible attempt to turn the Sept. 11 hijackings into a rollicking entertainment befitting a Jerry Bruckheimer action flick.

But the visceral punch of Greengrass' achievement hit me again and again on multiple levels as I watched the DVD of "United 93" (Universal Studios Home Entertainment). Just as this film so powerfully recreates the events of that day using unknown actors and real-life participants, a one-hour documentary adds heft and dimension to the story by showing us the tortured, conflicted and still-healing families.

Just as United 93 passengers joined to thwart terrorists targeting Washington, D.C. (the plane crashed near Shanksville, Pa., instead), their family members tell how they fell in line behind Greengrass' film — largely because, as one relative puts it, concerns over legacy outweighed concerns over privacy.

Another reacts this way to criticisms that Greengrass prematurely revisits the disaster: "Too soon? Not soon enough. We don't want them to be forgotten."

In less-skilled hands, the framing device — in which unknown actors meet family members of the dead passengers they portray — would constitute a recipe for mawkish disaster. But it works largely because the encounters flow like a home movie, without grating voice-over or a note of treacly music. Awkward moments hang; shed tears lack sentiment; the stories told clearly illustrate how these passengers lived.

In some cases, the revelations are spine-tingling. We see a teapot-size urn containing one victim's remains — composed, we are told, of about two dozen recovered, cremated body parts. In another scene, a mother reads her daughter's last journal entry, where the adolescent imagines a crash and floating above her dead body with glee. She then points out a frenetic sketch that eerily resembles a descending plane.

Instead of dwelling on this as a possible clairvoyant vision, the mother tears up and reacts as any caring parent would, focusing on the angst-ridden writings: "How did I not know this was going on in my daughter?"

It's possible the documentary deliberately bypasses friends and kin disappointed by the film. Yet that seems unlikely, given the stunning unity running through this group. They have become, as one of them says, an extended community — one linked and locked by terrible loss, but a community nonetheless.