With nods to classic and sub-classic sci-fi movies, " Monsters vs. Aliens," the first DreamWorks Animation effort created in 3-D, may appeal as much to grown-up cinephiles as to children. It's not often you see a kids' film full of references to "The Blob," "Mothra" and Stanley Kubrick's "Dr. Strangelove."
The very premise is a B-movie homage: In nondescript Modesto, Calif., pretty Susan (voiced by Reese Witherspoon) gets flattened by a glowing asteroid moments before her wedding to the local weatherman ( Paul Rudd, in a rare caddish role). Mid-vow, Susan grows into a lumbering giant - ker-pop goes that garter belt - and within moments she's pinned down, Gulliver-style, by government forces.
Enter Gen. W.R. Monger, a Strangelovian commando with the self-parodying growl of Kiefer Sutherland. Monger dumps Susan into an underground bunker with other bizarre creatures, namely the insectoid Dr. Cockroach ( Hugh Laurie), the amphibious Missing Link (Will Arnett), a brainless blob called B.O.B. ( Seth Rogen) and the screeching Insectosaurus. They're imprisoned to protect the public, Monger explains, though that will change.
Like many DreamWorks creations, the characters are ingeniously funny (B.O.B. is the result of a horrifying snack-food experiment), though not quite emotionally engaging. Susan's new size becomes a metaphor for self-empowerment - "I'll bet there isn't a jar on the planet I can't open," she marvels - but filmmakers Rob Letterman ("Shark Tale") and Conrad Vernon ("Shrek 2") don't give equal time to the other monsters.
Still, the 3-D animation is terrific: In one dazzling sequence, two behemoths reduce San Francisco to rubble. There also are moments of inspired lunacy, particularly from the fiendish but overly confident alien Galaxhar (Rainn Wilson) and his mirror image, The President ( Stephen Colbert, naturally). "Monsters vs. Aliens" may lack a bit of heart, but it more than compensates with intelligent humor.