I just love the Motion Picture Association of America and its touchingly unreliable ratings system. "TMNT," the latest installment in the Teenage Mutant Ninja Turtles franchise and the first computer-animated feature therein, carries a business-friendly PG rating for "animated action violence" as well as "some scary cartoon images," neither of which sound scary in the least. So, you know, bring the 2-year-olds.

Surprise! Besides being lame, cold, ugly-spirited and hard on the eyes, "TMNT" should've gotten a PG-13, since it's all head-banging and assaultive frenzy disguised as a story of how four brothers learn to fight as one. Producer Thomas K. Gray said in a recent interview that if this one's a hit, "the next one we will make PG-13, but we would prefer to make it R." Ideally a sequel would pit the turtles against the Spartans of "300" and the blood would fly oh so prettily.

To be fair, blood isn't the name of writer-director Kevin Munroe's game. Neither is cleverness or invention. "TMNT," the first screen outing for Donatello, Leonardo, Michelangelo and Raphael since the third live-action film 14 years ago, is in fact a sequel to the initial 1990 smash, which was based on all the comic books and TV series and toothpaste bearing the mutant shelled reptiles' logo.

The new film pits the quartet against the Foot Clan and a dozen-plus monsters unleashed by some ancient curse or other. In between "Death Wish"-style excursions designed to rid New York City of its criminal vermin, now and then one character accuses another of glorifying violence, "that brute vigilante junk." Talk about hypocrisy: Without the brute vigilante junk, this 82-minute picture would be approximately 2 minutes long.