The summer-movie season is a bastion of review-proof franchise flicks. First "Iron Man 2," and soon "Toy Story 3" and "The Twilight Saga: Eclipse" -- all these films and more were essentially guaranteed mega-box-office openings as soon as they got a green light.

Of course, that hasn't stopped critics from weighing in with opinions, positive and negative. Such is the case with "Shrek Forever After," the fourth and final installment of the green-ogre franchise. Hype it or slam it, the 3-D animated kids' movie might well pass the $100 million threshold during its opening weekend (which kicked off on Friday, May 21). Nonetheless, parents and their little ones want to know the bottom line: Does "Forever After" live up to the bar set by the previous installments?

Absolutely, argues Michael O'Sullivan in The Washington Post. "Believe it or not, there's life in the old boy yet," he wrote. "After a disappointing third outing, this 'Shrek' brings the cycle of fairy-tale-themed films to a fine finish."

The story finds Shrek in an "It's a Wonderful Life"-style alternate reality in which he was never born, and thus has no friends or family, no enduring connections, no source of happiness. It's a sort of series reboot for "Shrek," and not everyone is convinced the narrative switcheroo breathes new life into the franchise. "Though 'Shrek Forever After' has some clever lines -- notably more than in the third movie -- the pop-culture references and joyous spirit have been replaced by spurts of slapstick and contrived mania," said Claudia Puig of USA Today.

Opinions, no doubt, are split on "Shrek." But what everyone can agree on is that it looks visually stunning. "One of the nicest surprises of 'Forever After' is the near perfect marriage it achieves between the animation artistry, which is exceptional here, and the 3-D technology," Betsy Sharkey wrote in the Los Angeles Times. "Don't get me wrong, the effects are snazzy enough, and all sorts of things race off the screen. But they don't out-dazzle everything else, which is how it should be in my book, though some may wish for more wow."

So, how do stars Mike Myers, Cameron Diaz, Eddie Murphy and Antonio Banderas fair? Quite well, according to Mary Elizabeth Williams on Salon.com. "While Shrek himself, once again deftly voiced by the better-heard-and-not-seen Mike Myers, wrestles angst with aplomb, it's Fiona (Cameron Diaz) who emerges as the true hero of this installment," she wrote. "Diaz, a vastly underrated actress, has a natural affinity for the complexity of Fiona and gives her character both a warm maternal spark and a flinty protective shell. ... Bringing up the comic relief rear are Antonio Banderas as a now pampered, out-of-shape Puss in Boots and Eddie Murphy as the perpetually slow on the uptake Donkey, amazed that he's a dragon's babydaddy in an alternative reality."

The final word goes to Rene Rodriguez of the Miami Herald: "The movie is big-hearted and peppered with juicy throwaway bits: I liked the way the Gingerbread Man had to turn around one of the Three Blind Mice, who was cheering in the wrong direction, or the line by the ogre cook (Craig Robinson) about the need for a chimichanga stand on the battlefield, because everyone's going to be starving after waging war. 'Shrek Forever After' isn't essential, but it's breezy and likable and doesn't overstay its welcome -- the first summer movie thus far to deliver on its promise to put on a good show."

Check out everything we've got on "Shrek Forever After."

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