A detestable film that forces us to follow for eighty-eight minutes a couple of hateful psychopaths with a sick story that wants to be a very dark comedy and make fun of their gruesome atrocities - but everything is just too much bad taste to be remotely funny.

It's always painful when a promising director fails to live up to their burgeoning reputation. Through Down Terrace and Kill List, Ben Wheatley has established himself as one of the most exciting British film-makers in recent times, carving out a niche for himself in low-budget horrors and thrillers which marry unconventional storytelling to a fittingly gruesome aesthetic. But having delivered so well with straight material, Wheatley has now come unstuck with Sightseers. While it is technically as accomplished as his previous films, and possesses great potential in its main conceit, it ultimately fulfils on far too little of its promise. What should be a really great black comedy sputters and stumbles over 85 minutes, never justifying or meeting our expectations with either its story or humour. Sightseers is part of a long lineage of comedies build around the holiday-gone-wrong - or "sexual odyssey"-gone-wrong, if you will. Examples of this range from the infamously bawdy (Carry on Camping) to the darkly political (Mike Leigh's Nuts in May). And it's not just a parochial British trend: Jacques Tati's Mr. Hulot's Holiday revolves around the same basic idea of a person or persons going on holiday and leaving chaos in their wake. In other words, there is precedent for all of this, a series of beats or marks for any new director to hit. The thing is, Wheatley has spent his entire career openly eschewing precedent. Even though his films have been set in very specific, often well-worn genres, he always goes out of his way to confound our expectations, with plot, character and visual choices that often bemuse as much as they impress. When this works, as with Kill List, he's one of Britain's most exciting directors, capable of generating a unique sense of tension, forbidding and impending doom. When it doesn't, as with Sightseers, the film ends up as a collection of bits awkwardly lumped together. Wheatley's talent is such that I am loath to pigeon-hole him, but it may just be that comedy is not his thing. He is a very interesting and adept horror director, capable of capturing both gory brutality (Kill List) and deeply unsettling atmosphere (A Field in England). Most of all, he has a jet-black, almost misanthropic streak which manifests itself in the fates and nature of his characters, something which is naturally suited to horror. When he tries to apply the same principles but with jokes, it's either not funny or funny in a very awkward way. The secret to making a great black comedy is to introduce dark ideas or images to an audience and then give them a reason to laugh at it by building up an empathy with the leads. In Dr. Strangelove we laugh at the impending death of all humanity because we understand the absurd motivations of Colonel Jack D. Ripper, Major Kong or General Buck Turgidson. In Heathers we laugh at the deaths of the high school students because the film keeps us focussed on the plight of Veronica Sawyer and her complex, conflicted feelings towards JD. Sightseers' biggest problem is that both characters are pretty hateful - or at least so dislikeable that such levels of empathy become impossible. There are many films in which we are asked to empathise with serial killers (Kind Hearts and Coronets being another example), but the killers become memorable or emotionally engaging because they feel rounded and interesting. Here we are given a serial killer and a closeted, sheltered thirty-something, and all their back-story is either irritating or uninteresting. There's no real development beyond the woman becoming psychotic, and even that doesn't feel properly thought out. What makes this so annoying is that this central relationship could have been developed perfectly well in a number of ways. With a little more effort made to explain the characters - particularly Tina's development from horror to acceptance of Chris' actions - this could have been a very effective new take on thrillers based on lovers on the run. This would have worked either as a new take on Bonnie and Clyde or as a pastiche of alienation films from the late-1960s and early-1970s, like Zabriskie Point or Easy Rider. Alternatively, the material would have worked just as well had Wheatley played it straight, and made the story about Tina's reactions to being in love with a killer. Tina begins the film as a sheltered young woman, deeply in love with the man who will whisk her away from her overbearing mother and share with her a lot of new experiences (even if they are camping and visiting the tram museum). As the body count rises, she is torn between the horror she is caught up in and the love she has for Chris: even after what he has done, she knows handing him in will send her back to Mother, with all chance of happiness gone. Either approach would have made for an interesting, substantial and subversive film. But since Wheatley opts for neither, what we get is a film which is awkward, sluggish and very mean-spirited. When the first killing happens, there's a real frisson to the film, as we are uncertain as to whether it was something pre-meditated by Chris or a genuine accident. But most of the subsequent murders feel flippant and unjustified, and before long the film has become rather shapeless in both its plot and its character arcs. By the last 20 minutes we're crying out for a big showdown to finish things off, and while the ending has some logic, it feels unsatisfying. Considering the involvement of Edgar Wright at a production level, we might attempt to view Sightseers as a horror-comedy, rather than a black comedy per se. The distinction between the two, loosely speaking, is one of action vs. reaction: black comedies are usually built around protagonists doing nasty things (action), whereas horror-comedies are typically based around nasty things happening to people (reaction). But once again we draw a blank due to Wheatley's refusal to follow rules. There are two successful approaches to making a horror-comedy. One is to start out being funny and scary simultaneously, such as The Evil Dead; the other is to start out as a comedy and then gradually build up and transition to horror, like An American Werewolf in London. Wheatley, however, opts for neither, starting out with a horror movie and then expecting us to laugh for no good reason. Rather than work hard to make us understand the characters' reasons for murder, Sightseers simply asks us to laugh at murder as if it's inherently funny. To be fair, there are several aspects of Sightseers which are impressive, or at least capable. The film is very well shot by Wheatley's regular cinematographer Laurie Rose; he captures all the unappetising aspects of camping in great detail, and the pastel tones in the colour scheme contrast nicely with all the blood being spilled. The sound design is very good, particularly in painting a picture of the off-screen deaths, and the make-up effects are appealingly gruesome. Wheatley also uses hand-held camera very well, with the final scene on the viaduct taking on more of a vertiginous quality than would have been achieved with just a tripod. Sightseers is a frustrating disappointment, whose technical solidity can't make up for its failings as a comedy. It squanders most if not all its opportunities to makes its characters interesting or appealing, and Wheatley's approach to comedy leaves a lot to be desired. Wheatley remains a highly talented film-maker, as A Field in England clearly demonstrates, but this is one trip that he'll quickly will want to forget.