The Conversation (pg) <br></br> Bully (18) <br></br> The Mothman Prophecies (12) <br></br> If... (15)

A small book could be written on the marvellous intricacy and richness of Francis Ford Coppola's The Conversation, first seen in 1974 and now restored in a crisp new format for DVD. No matter how many times you watch this incomparable study in loneliness and paranoia, you can still pick up brilliant slivers of detail that may previously have gone unremarked. Coppola had made his name and fortune with The Godfather when he came to film this low-key story of wire-tappers and spooks, though he'd conceived it in outline years before Watergate entered the language.

From its stunning overhead shot of a busy Union Square and its shifting focus in the crowd – a chalk-faced mime, a nondescript guy in a mac, a perambulating couple – the film urgently draws us into its enigmatic action, and then tightens its grip. The man in the mac is Harry Caul (Gene Hackman), a surveillance agent out on a job. Harry steals privacy for a living, a professional expertise that has gradually infected his personal life; obsessed with secrecy, he pretends not to have a telephone, and locks his front door like a jailer, and alienates his girlfriend (Teri Garr) and his assistant (John Cazale), who both make the mistake of asking too many questions.

A Catholic, Harry is troubled by his conscience: it transpires that, after one of his celebrated professional coups some years back, a family of three were murdered. He disclaims any responsibility, but recognises that the case he's currently working on may endanger the lives of two young people. His meticulous sifting of the tapes of their conversation, and his repeated playing of individual sentences ("He'd kill us if he got the chance") may be Coppola's homage to Antonioni's Blowup, in which David Hemmings thinks he's discovered a murder by cropping and blowing up a photograph – and, by extension, comments on both the technology of filmmaking and the sinister erosion of privacy. However it's intended, it's extraordinarily haunting in the way it isolates Harry between his dread of disclosure and his helplessness to intervene.

One aspect that strikes afresh is David Shire's insinuating piano score, full of tense trills and discordancies. The Conversation may not have the bravura energy and grandeur of The Godfather pictures, and its appeal hasn't the same immediacy, but in its subtlety of texture and contemplative restraint it seems as great as anything Coppola has ever made.

I was unaware while watching Larry Clark's Bully that the film is based on a true story, and the realisation gave me a jolt. It shifts the whole emphasis of what seemed at first to be a comic-grotesque short story about bored American dropouts. Clark, whose movie Kids won him a certain notoriety a while back, is driven by a ravenous and prurient interest in teenage flesh and teenage sex (see inset). He uses his camera like a groper, running his eye over the coltish limbs of his young cast as they drift around their somnolent Florida suburb playing video games, lounging in bed and droning in voices hoarse with dope. Lisa (Rachel Miner) is in love with surf-boy Marty (Brad Renfro), but their lives are blighted by a vicious brute named Bobby (Nick Stahl), who abuses women and bullies Marty ruthlessly. Eventually, Lisa decides that the only way out of the problem is to kill Bobby, and she rounds up a gang of willing but extremely stupid accomplices to help her.

Clark's attitude is both provocative and baffling. Initially, he seems sympathetic to Marty, who may be a dim-bulb but hasn't any malice or cruelty in him, and is played in a sweetly vacant way by Brad Renfro. Marty has been humiliated all his life by Bobby, and his impulse to kill his tormentor is seen as the last resort of a desperately vulnerable kid. Then, once events take over, Clark seems almost to lose interest in the boy, and focuses instead on his affectless and inept friends as they flee from responsibility or cast around lamely for alibis. Suddenly, it seems, they deserve everything that's coming to them. The two sides of the film simply don't fit together: if Clark was going to tell a "true crime" story, which this is, why did he film so much of it as a Blank Generation satire? Bully has its moments, and some spot-on performances, but its creator is made to look even less trustworthy than he was before.

Supernatural thriller The Mothman Prophecies is also based on real events, though quite how "real" is debatable. Richard Gere plays a Washington Post reporter whose wife dies of a rare brain tumour after seeing (or hallucinating) a giant mothlike creature, whose appearance has been reported all over the town of Point Pleasant, West Virginia. This "mothman" supposedly presaged an actual disaster that befell the place in the late 1960s, a scenario that the director, Mark Pellington, has updated to so-so effect, casting Gere as the conduit of otherworldly intimations of doom. The director insists his film is "not sci-fi", though its components – strange voices down the phone, wild-eyed locals, inexplicable wounds – say otherwise. Less mothman than moth-eaten.

The week's other reissue has dated somewhat since 1968, though Lindsay Anderson's If... is still a pungent and intermittently amusing reminder of the hell to which English families used to send their offspring in the name of "a gentleman's education". The public school – noble display on the outside, raucous barbarity within – is revealed as so patently corrupt and foolish that Malcolm McDowell's hero no longer seems an anarchic outsider but a champion of decency. It's Nigel Molesworth come to life, with the sadistic gargoyles of Ronald Searle's spidery artwork represented by the "Whips" (prefects), those waistcoated cads whom Anderson appears to loathe far more passionately than the doltish, well-meaning staff above them.