Aliens are stupid, and because they don’t do their pre-invasion homework, they won’t last long.

It’s the only resonant detail of the narrative in this War of the Worlds, and that’s only because it’s utterly silly and quite self-importantly delivered by Morgan Freeman in an epilogue voiceover. (If that moment makes it sound like we should tune in next week for another installment, Freeman’s movie-opening recitation sounds like a trailer for what we’re about to watch.)

This story of from-nowhere, large-scale alien invasion is told from the points of view of deadbeat dad Ray (Tom Cruise), his son Robbie (Justin Chatwin) and daughter Rachel (Dakota Fanning). It quickly becomes a bad weekend to have the kids, as the trio embarks on a trek through a ravaged seaboard to find the kids’ mother (Miranda Otto) in Boston.

Director Steven Spielberg and star-producer Cruise’s modern-day variation on H.G. Wells’ tale occasionally shocks with unexpected brutality during its hellish, Apocalypse Now-style journey.

People are instantly incinerated by tripod war machines, an angry mob plays out a violent power struggle for one of the few still-running cars and militia mentality begins to take hold in a dark countryside basement.

The demolition of street corners, neighborhood churches and suburban homes is more emotionally identifiable than watching, for example, the Eiffel Tower topple. And Cruise, like many of the extras behind him, gets lost in this maelstrom. Bleeding him into the background of the nightmarish events is a wise choice over singling him out.

And some of the special effects are equally back-seated, allowing the tripods’ visual menace to gradually build. (It’s lame, though, when their attack foghorns sound like ominous Wagner chords.)

It’s a prelude to the crumble of Spielberg’s eye for spectacle, given his third-act cribbing both from Jurassic Park (look how that alien probe stalks just like a raptor) and Saving Private Ryan (is that the same shoulder-to-air missile launcher that took out the sniper?). And the invaders, like so many before them, should have stayed a faceless menace.

Spielberg’s storytelling side offers far too little of the interpersonal oomph he and Cruise seem so square-jawed on delivering. In the end, it’s only a few steps above a blow-stuff-up movie.

Matt Lauer might disagree, but Cruise really hasn’t been such a rampaging jerk since Magnolia. It’s a welcome change of pace for the actor, and he’s most surprisingly prickly in his early scenes of domestic tension — telling his remarried, pregnant wife “that’s a good look” for her and taking a game of catch with Robbie way beyond a Yankees-Red Sox fan rivalry.

But Ray quickly gets mired in hero-father mode, as he’s able to escape a truck tossed about by tentacles and set off a whole clip of grenades in a sticky situation. The movie never lets the full weight of what happens to Ray — whether it’s the foreign art of parenting or what ultimately transpires with a mildly pedophilic wacko (Tim Robbins) in that basement — rest on his shoulders.

At the level the movie is pitched at, it’s about what Ray learns, and there’s no palpable sense of the significant shift in his isolated world; Jurassic Park’s Dr. Grant arguably learned more about how to better communicate with children. But perhaps the tradeoff for a Spielberg film shorter than two hours is a clunkier resolution than most of his others.

Even in the filmmaker’s weaker work, there usually is the sense of a movie made and an experience felt. War of the Worlds feels like a mission completed to make a summer blockbuster of destruction and little more.