I would imagine that a few people (and only a few, as you'll be lucky to find it on the shelves of your local video rental store) who have picked up Chris Petit's Unrequited Love on the basis of its title alone, perhaps expecting a Richard Curtis penned romantic comedy, have received something of a start when they played the DVD. Maybe there were a few who took a cursory look at the back cover and observed that it was about stalking and were similarly misled into expecting a thriller in the mode of Fatal Attraction and its scruffy ilk. Even those familiar with the book on which the film is based (and I confess that I am not one of  them) will probably be ill prepared for what the film delivers.

Time Out film critic turned filmmaker and writer Chris Petit's cinema career spans over twenty-five years, and began auspiciously back in 1980 with Radio On, which was co-produced by Wim Wenders (along with Keith Griffiths, also the regular producer on the Quay Brothers films). It was followed by a compelling adaptation of P.D. James' An Unsuitable Job for a Woman, after which I moved away from London and lost touch with Petit's films, which should give you some idea of the sort of cinemas in which they played. They were never your standard multiplex fare (although Unsuitable Job should have reached a far bigger audience than it did), but in the years that followed, Petit appears to have all but rejected the concept of narrative cinema, and with it film as a recording and delivery medium.

Unrequited Love, which describes itself as 'a love story in long shot', is closer to an art installation piece than to traditional dramatic cinema, despite teasing early indications to the contrary. The opening sequence in particular, an almost amateurishly wobbly image that zooms out to place us in the position of unseen voyeur watching a woman through her own living room window at night, soon prompts the question of just who is stalking whom. Things do slowly become clearer, but are further complicated when the roles are later reversed, although even working out that this has happened is one of the many challenges the film offers for those who are game.

This narrative thread runs throughout the film but remains just that, a thread in a larger patchwork of ideas, images, opinions and theories, with even a little science and history thrown in. A cinematic collage of information and experiences relating to the issue of stalking, it presents nothing on a plate but is frequently suggestive of what it means to be stalked in a high tech, surveillance-heavy age, where video cameras, e-mail and text messaging have increased both the possibilities for communication and the potential for privacy invasion.

Information is presented in broken mirror fashion, shattered fragments of a narrative into which documentary and personal asides have been scattered. The action is seen largely from the viewpoint of others, whether it be point-of-view, video camera or mobile phone footage (the low-band recording format makes it hard to tell which of these you are watching for much of the time), the use of CCTV cameras a reminder that we are all effectively being stalked to some degree on a daily basis by people we will probably never meet. There is an almost complete absence of on-screen dialogue, with the non-diegetic soundtrack often at least partially disassociated from the images. E-mails and text messages are read, books quoted from, and views offered by the emotionally neutered voices of the central characters, sometimes underscored by a montage of sounds of communication and its abuse (ringing phones, modems, recorded advice on how to deal with nuisance callers).

All of this gives the film an intriguing but potentially disorientating cut-up quality, a touch of Chris Marker by way of Antony Balch, an approach that can suggest a randomness to the structure that has clearly alienated and annoyed some the film's less sympathetic viewers, prompting accusations of self-indulgent amateurism and landing it a shockingly low score on the IMDb. And although I can genuinely see where these criticisms are coming from, they have to be treated with caution – the IMDB score is (at the time of writing) based on just 12 votes, hardly a representative spread, and the only posted comment is woefully inaccurate in some of its observations.

There were certainly moments when a wry grin crossed my face, such as the replayed station meeting that feels a little like a demo of the effects filters available on editing systems like on Avid or Final Cut Pro, or the too-familiar and rather sniffy favouring of Antonioni (the artist) over Hitchcock (the populist) in asides that feel slightly sidetracked and play almost like intellectual daydreaming. But then it seems slightly absurd to ask experimental cinema, which by its very nature has no set rules, to conform to expectations or the formal guidelines of film grammar. More than any other film form, it's effectiveness or otherwise relies on a relationship between the filmmaker and the individual viewer that does not necessarily have to be a comfortable or straightforward one, and any such work is almost pre-destined to annoy more people than it pleases.

The question of whether the film works for me is one I am not sure I yet have a final answer to. The narrative, such as it is, is a puzzle that requires serious concentration to piece together, and I can't say the result added to my knowledge or understanding of the whole issue of stalking or connected me emotionally to those involved. But there are many moments when the artistry of the imagery and/or soundtrack prove genuinely mesmerising, not least the strangely captivating still frames of the city at night, or the overhead surveillance camera that graphically tracks the movements of the people it observes. The film as a whole also creates a surprisingly vivid feel for the experience of being on both sides of the stalking process and the sense of isolation that this can create, and despite the cut-up quality of the narrative a strong continuity is nonetheless provided by Mario Schneider, Thies Isaak Streifinger and Cornelius Renz's sometimes strikingly effective score.

As a viewing experience Unrequited Love can occasionally prove frustrating, but it's also unusual, challenging and thought-provoking, positive and encouraging qualities in these increasingly dumbed-down days. One way to categorise the film, if you really had to, would be as cubist cinema, an apt description for a work in which the broken mirror of its narrative is re-assembled into a new whole that may fragment and even abstract the image, but in the process allows us to look at it in new and interesting ways.

Shot on a variety of digital formats, including mobile phones and  Digital-8, none of which has undergone any processing, the picture here looks as good as these low band digital formats allow. Contrast is largely excellent, and colour reproduction is fine when lighting permits. Grain and digital noise are inevitably visible when light levels drop, and white are sometimes burned out. The surprise if how good the quality of some of the Leipzig CCTV footage looks, the level of detail better than some of the camcorder material. The framing is 4:3, which was the original aspect ratio.

The Dolby stereo 2.0 soundtrack has volume, clarity and punch, the music sound particularly good, although there is a slight treble bias to the voice-overs.

The Interview with Chris Petit (27:02) is a very worthwhile and interesting piece in which the director talks about the process of adapting and interpreting Gregory Dart's book, the incorporation of film and literary references, the choice of recording formats and its relation to the BBC's later reporting of the July 2005 London bombing, the casting, the influence of Bresson and Ophuls, working in Leipzig, and how funding issues shaped part of the film.

Equally worthwhile is the Interview with Gregory Dart (24:29), in which the writer of the original novel covers the process of constructing and shaping the story, his own experiences with being stalked, the differences between the film and the book, the role modern technology plays in the stalking process, the experience of essentially playing himself in the film, stalkers as "fundamentalists of love" and the nature of stalking itself.

Finally there is a Photo Gallery, which is essentially a large and rolling collection of screen grabs that replay the film as still images. This one was lost on me.

Although originally screened on Channel 4 in September 2006, Chris Petit suggests in the interview on this disc that in retrospect the internet might have been a more logical broadcast medium for the piece. That may well score on instant accessibility, but the DVD wins over it on image quality and certainly has the edge on the TV broadcast through the removal of the commercial breaks, whose vacuous glossiness would no doubt sit uneasily with the more down-and-digital imagery of Petit's film. Reaction to it is likely to be fairly polarised, but many of those who liked it have really liked it, and I have a feeling this is work that will grow on me with successive viewings.