Like books, it's often a bad idea to judge a game by its cover – or even by its first chapters, as tempting as just giving up can be. For the opening hour or two of this spin-off, the only real question was whether Game of Thrones RPG was merely comedy-bad or active, outright heresy against George R R Martin's amazing, if increasingly bloated, fantasy series. Awful graphics. Tedious combat. Voice-acting that smacks of a producer leaning out of a window one Sunday and yelling at random passers-by, “Hey! Want to be in a licensed abomination?” I've had more enjoyable dental appointments.

After a while though, almost apologetically, things started to click. To some extent. A bit. Even at its very best, Game of Thrones is a thoroughly mediocre RPG. It does however end up a mediocre RPG that at least tells a decent story. Set just before and during the first book, it follows two seemingly unrelated characters: a brother of the Night's Watch called Mors, whose gravelvoiced authority is sadly undercut by the number of times he has to intone the name “Poddy”, and a Red Priest, Alester. Both are brought together by a mysterious young woman on the run, for reasons I won't spoil but which tie into the first novel pretty well, with chapters jumping between their individual adventures.

The result is hardly The Witcher 2, but the twists and turns of the plot are oddly compelling, with several nasty scenes and a fair amount of control over how cynical you want your heroes to be. Alester's story, for instance, revolves around him returning to take control of his home town, Riverspring. You get to decide whether he's a man of the people or one of Westeros' typically dickish lords. Mors on the other hand is a hardline black brother, but one still willing to turn the occasional blind eye when warranted. Both also have some fun unique powers – Mors can possess his hilariously ugly dog for tracking and stealth purposes, and Alester can call on his god R'hllor to manipulate fire. Those are a little showy given the nature of magic in at least civilised parts of Westeros like King's Landing, if not typically as outlandish as outright hurling fireballs in the streets like a classic RPG mage type.

The story is linear to the point of often feeling like a corridor shooter with RPG combat, although there is a dusting of sub-quests sprinkled in and more than a few moments where your decisions have at least some minor impact later on. The writing rarely has the sense of punch and threat that makes the books or TV series so effective, and often writes cheques that the engine and acting simply can't cash. The inevitable brothel scenes especially are hilariously coy compared with the TV show . Still, it's a solid story reasonably told, and becomes oddly compelling once it gets going.

This is all the more impressive next to the shoddy design. Game of Thrones RPG is riddled with grating wait-a-minute stuff, like trying to pretend that four guys outside a castle constitute a riot, hilariously coy handling of the series' sexual content, and explaining its combat so poorly that you're almost guaranteed to get destroyed once you get out of the unofficial tutorial areas and face a few street thugs.

Even when you 'get' it, combat feels weak and ill-thought out - bland, uninteresting, and based almost entirely around status effects. Use skill to make enemy bleed (or whatever). Use skill that does extra damage against bleeding enemies. Repeat until all the enemy's blood has gone. Other elements are simply out of step with the source material, such as glugging down health potions mid-fight and Alester's more advanced fire powers. Honestly, it's best to just switch the difficulty to Casual and focus on the story. Most regular fights become trivial, though there are still a few tough ones to handle.

Ultimately, Game of Thrones is a frustrating, ugly, low-rent RPG that's flawed in almost every way and difficult to impossible to recommend – but which fans still might enjoy more than they probably should. At the very least, it's not a lazy cash-in, just one trying its best on far too small a budget. If you can tolerate that – and yes, it's a lot to tolerate – don't necessarily run screaming from its score.