Gone Baby Gone (15) Director: Ben Affleck ***

Mongol (15) Director: Sergei Bodrov **

Superhero Movie (12A) Director: Craig Mazin *

Prom Night (15) Director: Nelson McCormick (No stars)

THE actor Ben Affleck has had a rough old time in recent years, due to a combination of bad career choices (Pearl Harbour, Daredevil) and a torrid engagement with Jennifer Lopez. But he's recently redeemed himself, on both sides of the camera: with last year's excellent performance as the TV superman George Reeves in Hollywoodland; and now, with assured and involving directorial debut, Gone Baby Gone.

Affleck has returned to the blue-collar Boston he wrote about, with his friend Matt Damon, in their breakthrough film Good Will Hunting. That film was an exercise in wish-fulfilment, featuring a young man who escapes his limited world through the good luck of his IQ. This is a much more hardboiled affair, as Affleck adapts a detective novel by Dennis Lehane, about the abduction of a four-year-old child and the myriad moral questions it raises among the family, cops and, primarily, two young private eyes involved in the search.

Like all good detective yarns, this has a strong focal presence surrounded by a gallery of fruity characters. The focus is Patrick Kenzie (Affleck's brother Casey), a private eye who, with his partner Angie Gennaro (Michelle Monaghan), is asked by the missing girl's aunt to help the police hunt for the child. Kenzie is a local, and quickly uses his old neighbourhood contacts to make progress on the case. But he and Gennaro have to engage with widespread hostility, not only from the police (Morgan Freeman and Ed Harris) but, more surprisingly, from the girl's mother.

Amy Ryan's portrait of a low-life, drug-taking floozy with no evident care for her child is richly drawn, even daring. The mother's unattractiveness and our lack of sympathy for her are fundamental to the fascinating moral maze in which all of the characters become lost.

The best things in the film, aside from the questions it raises about the right and wrong of a child's custody, are offered by Affleck's informed depiction of a down-at-heel, struggling community in which too many people "fall between the cracks", and by his cast, with Harris (dangerous and funny as the Louisiana cop), Amy Madigan (as the caring aunt) and Ryan.

The weakest aspect, and one which almost undermines the whole film, lies in the source itself. As we know from Mystic River (filmed by Clint Eastwood), Lehane isn't adverse to contrivance. The way that this plot plays out is often clichéd and preposterous, leaving one nodding in approval when one character laments, "you could have just reported her to social services". Nothing so prosaic as that, for a writer always striving for his Greek tragedy.

The Russian-made historical epic Mongol promises more than it delivers, namely a full-blown imagining of the life and conquests of Genghis Khan. In the end it's a taster only - a prequel commendable for its detailing of the life of the nomadic Mongolian tribes of the 12th century, impressive in its battle scenes, but with a repetitive, one-note story. There may not be a great deal known about the warrior, but to suggest his career was due to the love for, and of, a good woman is a mite romantic.

Director Sergei Bodrov charts the tough early life of Temudgin, as he was first known, from childhood to the battle against his Mongol enemies that united the tribes. It ends before Khan turned his attentions further afield.

Mongol is a tale of character-building, rather than empire-building. As a boy, he has to cope with the murder of his father and threats to his own life, and as a young man, he deals with the kidnap of his wife and years spent in a foreign jail.

Japanese actor Asano Tadanobu plays the older Temudgin as a thoughtful, good-hearted leader, but is too devoid of charisma to engage us sufficiently through a drawn-out adventure - one frustratingly without its punchline.

The best film spoofs are, crucially, of situations or genres that take themselves seriously. Spinal Tap is a masterpiece because heavy metal bands of the 1970s really did believe in the hair, the crotch-cleaving poses and their daft lyrics. Similarly, Airplane is very good because disaster movies, with their all-embracing demographic of victims, are so very grave.

So Superhero Movie, which follows the familiar misadventures of Rick Riker, aka The Dragonfly, is a redundant exercise from the start. Where's the point in spoofing the Spiderman, Batman, X-Men or Fantastic Four movies when they already have tongues healthily in cheek?

It doesn't help that the level of humour is of the playground variety, replete with enough farts to fill a store of Whoopee Cushions, mixed with the sort of B-list celebrity point-scoring used by that other, recent, lame spoof, Meet The Spartans. It's surprising that Airplane creator David Zucker is behind this, and sad that his old star Leslie Nielsen has been wheeled out for the poorer jokes.

An even more unoriginal offering, yet without even an occasional chuckle to lighten the load, is Prom Night. You know the scenario: mad killer escapes the asylum and returns to town to kill the female object of his obsession. The Halloweens used a variation on the formula to scare the pants off us, the Screams to make us laugh. But Prom Night has neither chills nor irony, merely presenting a bland collection of teens who, during their end-of-school celebrations, parade themselves dumbly before an indiscriminate blade. This does remind us that the prom is one of America's most horrid inventions. But Brian De Palma, with Carrie, made a much better fist of spoiling the party.