I'll admit, I was completely cowardly... I read as many user reviews about this film as possible, before offering a critique. Why? Because when attempting assessment of controversial material, its a good idea to find the "middle ground".
As one would suspect, reviewers either loved or hated this movie. Since we're on a movie review site, I found myself thinking: Is this an eerie, atmospheric shocker like Polanski's work? No... Hard Candy is shocking in places, but lacks atmosphere and an eerie edge due to its setting.
Do we have a tense and driven psychological thriller in the style of Hitchcock? Not really... Although there's moments when Hard Candy is nearly as good, this movie lacks the subtle symbolism and driven power of Hitchcock at his best.
So, what are we left with? Well... A noble but flawed project, I think. Noble because mainstream movies so very rarely attempt to grapple with difficult issues like internet pedophilia and (female) sadism. Flawed because of the writing.
The central ethos of Hard Candy asks us to accept that torture and mental cruelty is an acceptable outcome, when victims "turn" and become the attackers-that-were-attacked. The film-makers are over-manipulative here, because they know many of us wish to see dangerous sexual criminals roasted over a hot fire - but this is a medieval idea - and does not prevent crime...
Faulty logic is at work when victim becomes attacker (albeit in a different way). It's a kind of vigilante-style response, much loved by film-makers (because of it's simple, direct message). Yet, the real issues as to why crime occurs are overlooked. In fact, the real issues are side-stepped completely in Hard Candy.
Why Hayley is so driven, organized and determined to reek vengeance on this hapless photographer isn't clear to me - I think the inference is that she knew (or was) one of Jeff's victims. We have to wait to the end of the movie for this vital information - The wait's a long one and it seemed fudged.
The characters' back stories just aren't well-developed enough for us, the audience, to make clear judgments about whom we should be supporting. Stephen King's characters, for example, are much more rounded and believable.