Dir: Kevin Munroe. US. 2007. 87mins.

Seventeen years after their cinematic debut, the Teenage Mutant Ninja Turtles return with their sweetness and boyish tomfoolery intact. TMNT may substitute CG animation for the earlier films' live-action treatment, but the strongest ingredient remains the four reptiles' incorrigible charm, which easily outclasses a muddled storyline and the film-makers' concessions to the prepubescent male audience.

Opening March 23 in the US, this PG-rated Warner Bros. release would love to garner anything close to the $135m brought in domestically by the first Turtles film back in March 1990. (Two subsequent sequels collectively netted approximately $120m in the States.) But in a crowded teen marketplace - which includes New Line's family film The Last Mimzy (March 23) and Disney's animated Meet The Robinsons (March 30) - TMNT will rely on brand appeal and a reinvigorated CG look to separate itself from the pack.

The film also hits most international territories on March 23, quickly expanding in the following weeks. Foreign audiences may be turned off by the Turtles' heavy use of American colloquialisms, but the martial-arts fighting and Hong Kong-derived animation should prove universally appealing. Regardless, expect strong ancillary and DVD performance among the teen and preteen set.

Living in Manhattan's sewers, the Teenage Mutant Ninja Turtles - reluctant leader Leonardo (Taylor), goofy Michelangelo (Kelley), nerdy Donatello (Whitfield), and hot-headed Raphael (North) - do battle with evil billionaire Maximillian J Winters (Stewart) who has recruited an army of stone soldiers to track down ancient monsters who live in hiding in New York City. The Turtles must defeat the soldiers and monsters while uncovering the motives for Maximillian's plan.

Writer-director Kevin Munroe made his name as an animation artist and comic-book writer, and consequently TMNT boasts an agreeably slick, anime-influenced sheen that gives New York's skyscrapers and underground sewer system a noir-heavy atmosphere.

But, more importantly, Munroe stays faithful to the reptile protagonists' chief appeal. Created by Peter Laird and Kevin Eastman in the mid-'80s, the Turtles resemble other superheroes with their courage and crime-fighting skills, but their charm comes from the knowledge that, even though they're mutants who are also world-class ninjas, they are at heart just adorably typical teenage brothers: bickering, cracking lame jokes, eating pizza, and fending off rampant insecurity.

Jim Henson's Creature Shop designed the Turtles for the original live-action trilogy, lending the characters a warmth and humanity that gave them expressiveness and vulnerability. TMNT sacrifices some of that humanity because of its sleek animation, but the basic character traits of each Turtle manage to shine through nonetheless.

In fact, TMNT works best when Munroe moves away from his plot and simply focuses on the Turtles' sibling rivalry. So many films geared toward young people wield a cynical, achingly hip attitude, fearful of exposing any real emotion, but TMNT possesses a remarkably kind spirit.

Despite the action sequences and violence, Munroe's feature-length debut shows no blood or even anyone dying. The movie's sweetness - and its heartfelt paean to family - is its secret weapon, and Turtle actors Taylor and North both give strong performances, creating empathetic characters without dipping into sappiness.

Unfortunately, TMNT knows its core audience will be young boys, and the movie caters to them too easily, shoving obnoxious heavy metal onto the soundtrack and filling the screenplay with many awkwardly 'cool' lines which hit the ground with a thud.

Additionally, pacing and plotting prove to be constant liabilities. At less than 90 minutes, including lengthy credits, the movie takes an inordinate amount of time setting up the villains' motives, as well as reuniting the Turtles, who before the film begins have drifted apart.

Later, Munroe strands our heroes in a story that's needlessly convoluted, leading to an overblown battle-scene finale that barely makes any sense.

The CGI, overseen by Hong Kong animation director Kim Ooi, effectively conveys a stylised Manhattan with hints of futuristic architecture. The fight sequences, filled with swordplay and hand-to-hand combat, reference Asian cinema but have more freedom of movement than the typical wirework martial-arts spectacle can allow.

The animation is less successful with the human characters, however, as they seem too anime-influenced for the rest of TMNT's mostly realistic environment.

On the whole, TMNT is a promising reintroduction marred by commercial calculation. Back from retirement, the Turtles remain a lively quartet - now they just need a movie that's equally likable.

Production companies/backers
Warner Bros Pictures
The Weinstein Company
Imagi Animation Studios

US distribution
Warner Bros Pictures

International distribution
Warner Bros Pictures
The Weinstein Company

Thomas K Gray
H Galen Walker
Paul Wang

Executive producers
Francis Kao
Peter Laird
Gary Richardson
Frederick U Fierst

Kevin Munroe based on characters created by Peter Laird and Kevin Eastman

Steve Lumley

John Damien Ryan

Production design
Simon Murton

Klaus Badelt

Main cast
Chris Evans
Sarah Michelle Gellar
Kevin Smith
Patrick Stewart
Ziyi Zhang
Laurence Fishburne
Mitchell Whitfield
James Arnold Taylor
Mikey Kelley
Nolan North