It's the only rational explanation. Despite an exhaustive search of GPHQ for hidden pinhole cameras and illicit recording equipment (which managed to find nothing but our copy of Naughty Bear under the sofa after a perfect post-review parabolic flight) it's obvious that Deathly Hallows is cruel attempt to humiliate us for the pleasure of some sick audience somewhere.

So convinced of this am I, I've armed myself with our Mafia II desk lamp, which I shall take great pleasure in swinging wildly when Ashton Kutcher or his lesser-paid Kiwi alternate peels off a moustache and glibly points out that this broken, buggy game is the centrepiece in an elaborate set-up.

It's not just that Deathly Hallows is poorly conceived. The punchline here is that it's a Harry Potter game. Dreaming up new characters or environments is unncessary. There's no need to hire a bunch of experts to create new worlds, languages or themes. Anyone with a library card and an afternoon spare could sketch out a fairly compelling narrative to base a game upon, so quite how Deathly Hallows has such a nonsensical plot is completely beyond explanation.

The opening stage prepares the player for the kind of unsatisfying gameplay they're likely to face for the next six hours, or until the sweet, sweet release of death takes them. Flying shotgun in Hagrid's dubiously constructed sidecar and blasting Death Eaters is exciting for exactly fourteen seconds, so imagine the joy when forced to endure multiple incoming waves over and over whilst shouting "Stupefy" in an annoyingly repetitive fashion. There are detention camps in Cuba with a higher level of replayability than this.

Back on the ground, Harry is gradually introduced to a plot so thin it could get away with a convincing live performance of "We've Only Just Begun". In the book, Harry has left Hogworts in an attempt to defeat the evil Voldemort, which marks a turning point in the ongoing struggle between good and evil, and a significant bookend to the series as a whole. In the game, this translates to Harry wandering aimlessly though one boring set piece after the other, randomly shooting at uniform enemies with spells that show less variety than a season of House.

Indeed, if you've read the book, the only new magic you'll find in the game is the vanishing trick whereby your wallet becomes instantly lighter for no appreciable benefit.

Developer Bright Lights had attempted to provide a combat twist by equipping Harry with a Cloak of Invisibility, which is used to sneak around various levels to gather intelligence, or simply break the combat entirely by standing around doing nothing until it's all over. Equipping the coat switches the perspective to first-person, narrows an already painfully close field of view and removes the ability to run. The coat is powered by a depleting energy bar, which can only be topped up by standing still. As bystanders are automatically tracked to the invisible Harry, completing a mission isn't so much a matter of chance as sheer determination to stick with playing the game after repeatedly failing through no real fault of your own.

Despite managing to create character models that, given liberal applications of Vaseline to your television screen, appear roughly similar to the actors in the movie, the animation is atrocious. The lip-syncing, in particular, bears no resemblance whatsoever to the voicing, providing the unnerving impression that Bruce Lee might just show up at some stage. Regrettably, he doesn't, and I don't even like Bruce Lee.

The influential actors we've followed for years now, Daniel Radcliffe, Emma Watson, Alan Rickman, Robbie Coltrane, are all still with us. That is, they're alive, somewhere. They certainly haven't contributed in any way to this game. The only actor of any mention who didn't get the boycott memo, Rupert Grint, sounds like he'd had enough of the last ten years of Potter nonsense and would rather be down the pub trying to find out what happened to his youth.

Deathly Hallows introduces a cover system which succeeds in adding another layer of infuriation to the mix. It manages to be clumsy, impractical and even breaks the combat by blocking outgoing spells with regular monotony. It's also entirely unnecessary, as most enemies can be destroyed by casting a protection spell and spamming Stupefy until they drop. Just don't cast Confringo at the same time however, it'll blow up like a blocked kettle.

Kinect is supported, and to be fair this does extend the enjoyment factor by at least another minute. Playing the included mini-game (essentially a rail shooter) by waving your arms around provides a nice deviation from the snorefest of the base game. Unfortunately, unless you can satisfy the multiple criteria of owning an Xbox, being a Harry Potter fan, and the world's first recipient of a double-bionic-arm transplant, you'll probably grow tired of it in short order.

Deathly Hallows is really indicative of the kind of poor design shown in most movie-to-game adaptations, yet manages to fall short of even our lowest expectations. The frustration is compounded by the absolute lack of care from anyone along the entire design process as to what kind of a mess they've inflicted on unsuspecting gamers worldwide. It couldn't be a more obvious cash grab if EA donned a balaclava, stole an Armourguard truck and drove it through J.K. Rowling's country manor house before reversing and shouting "cheese it!"

Even the most ardent of fans are likely to stab you in the throat if they find this in a stocking come Christmas, so do yourself a favour and avoid.