And Game of Thrones was from HBO. The explosion of quality dramatic television series coming out of the US post-The Sopranos is hardly news. I didn’t know the original George R.R. Martin novels, but a long-form fantasy series as good as Deadwood or The Wire? Sign me up.

Fantasy (like science fiction) is a genre in ongoing conversation with itself, where current stories take up elements and arguments from previous stories to expand upon or refute. It seemed fairly clear to me from the start that Game of Thrones wanted to take the clichés that had built up around the fantasy genre since Tolkien and rub their noses in the dirt.

In reality, ye olden times were muddy and bloody and full of brutality, where the ideas of honour and gallantry were honoured almost entirely in the breech and only the harsh and brutal – the bad guys in any other series – would have survived. Having drifted away from fantasy in part because of my disinterest in the clichés, the idea of a series that would expose them to the harsh light of reality cheered me no end.

Of course, Game of Thrones doesn’t really want to bring reality to a fantasy world. It slaps a bit of mud on it and piles on the nudity, but beneath it all, the clichés still tick over. The brave knight might be a woman, the cunning hero might be a dwarf, the wise ruler might be an ocean away waiting for her dragons to grow up, but deep down all that’s changed is the casting. Still, that’s hardly a fatal flaw.

What was more deadly to my enjoyment was the utter seriousness with which it took itself. Like the Batman films, which daren’t crack a smile lest we realise that hang on, we’re watching a movie about a guy who dresses up as a bat, Game of Thrones is a basically silly concept (Dragons? Giants? Snow zombies? Assassins made of smoke? How do all these poverty-stricken medieval types manage to make such fancy costumes? What good are all those castles doing on top of crags in the middle of nowhere?) that can’t acknowledge its silliness for fear the whole structure will collapse.

Fantasy (and science fiction for that matter) requires a lot of world-building, and if you don’t take world-building seriously, the whole thing falls in a heap. In a drama set in the real world, you can mine humour from the way the world is or the way that people act. In a fantasy, doing that only draws attention to the fact that the world isn’t like this, and people aren’t like that. So getting laughs out of dragons or the wacky uneven seasons or the way all the endless sex slaves are really hot is out: Game of Thrones does the best it can at wringing laughs out of character interaction and physical bungling, but most of the characters are too thinly drawn for even that. (Tyrion only gets to be witty because that’s his thing.)

Ah, the characters. Producers Dan Weiss and David Benioff are often praised for their casting; a less charitable reviewer than I would suggest that’s because the casting has to do almost all the work when it comes to making the characters live. Many only get a handful of lines per episode, when they even appear in every episode; in situations like that, a suitable face will take you a lot further than the ability to bring a character to life through words and gesture.

This dour sourness – this teenage idea that the only way to be taken seriously is to be serious – mistakes length for depth. We’re up to season three now and fans of the books are saying things like ’ooh, it’s about to get really good now‘ (okay, it’s more like ‘This season’s set to be disaster porn – book fans are especially excited about season three because they cannot wait to see terrible things happen to important characters.’ Deadwood, which for mine is one of the best television series of the current age, only had three seasons. The Wire, which is the best series of the current age, only had five; likewise with Breaking Bad. Mad Men is set to finish with its seventh season. Meanwhile, we’re told that Game of Thrones is probably going to cover the events of George R.R. Martin’s third book in its third and fourth seasons.

If the rest of the books (five have been published, with at least another two to come) take up that much television real estate, we’re talking about a twelve-season series. That’s a soap opera. Killing Ned Stark in season one when he looked like the main character and Game of Thrones looked like a fantasy version of The Sopranos wasn’t a shockingly bold narrative twist; it merely turned the series into an endless horror movie where anyone can die at any time. But you can’t sustain that tension over twelve years; you can’t sustain it over twelve episodes. Eventually you become numb to the horror, and what then? What is Game of Thrones actually about?

The fantasy elements are downplayed so as not to distract from the realism of the show; the realistic elements of the show are sketched in over-the-top fantasy clichés. Individual stories are interesting, but they’re only handed out in bite-sized portions, while the big picture feels like a vast novelisation of a fantasy war-gaming session, where armies clash to and fro across a landscape that’s just lines on a map. It’s a skinfest soap opera aimed at people who are really into costuming and swords.

I’ll keep watching though. I don’t want to miss the part where the snow zombies eat everyone.