“War of the Worlds” producer Kathleen Kennedy, who has worked with Steven Spielberg since 1979’s “1941,” still remembers the controversy that erupted in the summer of 1984, when the PG-rated “Gremlins” and “Indiana Jones and the Temple of Doom” scared so many kids, it led the Motion Picture Association of America to create a new rating: PG-13.

“The acknowledgement that we’re making movies for a PG-13 audience is something we take very seriously,” she says. “Determining where that line is an interesting discussion, and it’s a continuing discussion because the audience keeps evolving. With this movie, we had a lot of discussions about the aliens’ death ray and how it kills people.”

Kennedy says early concepts included the old-fashioned “people bursting into flame” before Spielberg came up “with this oddly spiritual idea of turning to stone and dust, and their clothes launching into the air like spirits. He seized upon that as a way to make it less gruesome and less violent for a PG-13 audience.”

Still, “War of the Worlds” is pretty much relentless from the moment the aliens launch their first volley against planet Earth, and although the movie does not contain much blood, there is enough intensity, nightmarish imagery (like a shot of a river crowded with floating corpses) and thematic elements in the story to thoroughly scare grown-ups, not to mention young children.