Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

You've never seen anything like HBO's Game of Thrones before. Lavish, bloody, dark, weird and sometimes amazingly sweet, the cable channel's adaptation of George R.R. Martin's bestselling book series delivers the goods.

We've seen the first six episodes, and here's our spoiler-free preview of them. In a nutshell: the series features a host of astonishingly powerful performances that bring a depth and maturity that you seldom see on television, in any genre. And it looks absolutely gorgeous.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

Even if you haven't read the four books published so far, you've probably heard the buzz about Martin's series, in which death and misfortune spare nobody, and every character is flawed in a different way. Martin's greatest achievement might be that he took the mock-Medieval setting that was the home of so much simplistic storytelling and used it to tell a grown-up story. Plus where other authors struggle to make you identify with one character, Martin manages to make you love a host of deeply messed-up humans.

The good news is that the producers of HBO's Game of Thrones series have managed to bring these strengths to the screen, and have made shockingly few compromises along the way.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

The HBO series approaches Martin's A Song of Ice and Fire as what it is: a character-focused drama, in which the plot twists are not nearly as important as what's going on inside people's heads and hearts. It would be easy to get fixated on the MacGuffins and political machinations, and treat Game of Thrones as a plot-driven saga, but the show takes its time and lets the characters breathe, showing us just what makes each of them tick. Most of all, it never feels rushed, even as it tries to squeeze a massive book into 10 episodes of television.

The cast is almost entirely perfect, and the actors really seem to inhabit these characters — there are lots of little moments of grief or joy or deep, bitter ambivalence that really shine through. The two stars are definitely Sean Bean as the noble but shortsighted Eddard "Ned" Stark, and Peter Dinklage as the mocking, pampered dwarf Tyrion Lannister. But a host of other characters really stand out in the television version — including a few characters who actually gain a bit more complexity and vividness in the hands of gifted actors.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

If you've read the books, there are definitely some places where you'll find yourself missing a few details, or regretting a few minor changes the television version made — but there are also a few places where you might wind up feeling like the TV version made an improvement. In particular, I had severe misgivings about the portrayal of the exiled Lord Viserys Targaryen, but wound up feeling like the slightly more nuanced television version worked better than the more one-note book version.

And yes, it's utterly gorgeous — as you've already seen from the trailers and stills. This is a show that has had some serious money thrown at it.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

Most of the potential audience for this series, of course, consists of people who haven't read the books at all. You might fear that the intricacy and sprawl of Martin's saga would make it hard to follow without an ever-present narrator explaining stuff. After all, there are dozens of characters, several of whom play a major role in the first book.

For people who haven't read the books, there's good news and bad news. The good news is, the performances are engaging enough that you'll be pulled along without needing to understand every detail of the complex backstory at first. Sean Bean, in particular, occupies a lot of screentime in the first episode and you can easily think of him as the show's main character, and follow his story until you figure out who all these other people are.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

The bad news is, it is a bit confusing. There's no way around it — large amounts of backstory are alluded to and hashed out, and you might find yourself wishing for a "pop-up video" style explanation of exactly who was betrothed to whose sister 10 years earlier. I have a feeling neophytes will either want to watch this with someone who's read the books, or have Westeros.org and ToweroftheHand.com handy as they watch, or else just re-watch the first episode a second time to get all the stuff they missed the first time. Luckily, it's good enough that watching the first episode twice isn't really a hardship.

In an attempt to make the story easier to follow, and flesh out some of the characters who don't get as much space in the book, the producers have added a number of scenes that aren't in the book. Because Martin has several viewpoint characters in the first book, we don't get to see stuff that happens when one of those characters isn't present. But on television, no such limitation exists, so we get to see what some of the characters are up to when Ned Stark, Bran Stark, Sansa Stark, Tyrion Lannister, Jon Snow, Daenerys and the others aren't around.

Spoiler-Free Preview: Game of Thrones really is an astonishing achievement

These newly added scenes are hit and miss, to be honest — at times, they come across as slightly clunky, and they often drag on because the characters don't really seem to have that much to say to each other. There are a few new scenes, in particular, which feel like writing exercises rather than fully fledged scenes that carry storytelling water. On the other hand, a few of these new scenes do feel valuable, especially for helping introduce these characters to people who haven't read the books.

All in all, though, the Game of Thrones miniseries is every bit as addictive as the books. The producers have managed to do justice to George R.R. Martin's achievement — and create something that stands on its own as a great piece of television. Highly recommended.

Game of Thrones debuts this Sunday at 9 PM on HBO.