So I watched it. And you know - it isn't half bad.
The plot is the traditional one: weary old King Hrothgar, great hall, monster attacks the Danes at night, etc etc. The twists in this particular version are that they have tried their damnedest to make it look historically plausible - proper Viking architecture & boats, epileptic Irish priests bringing the Word of God to the heathen etc - and that sympathy rests firmly with Grendel. Who isn't a monster despite being described as a "troll" throughout: he's clearly a Neanderthal. So Beowulf finds that his enemy (who bears a very particular grudge against Hrothgar) is intelligent and not interested in fighting him. Which is a bit embarrassing for the poor hero...
Filming was done in Iceland in the teeth of terrible climactic conditions, and the landscape looks stunning in every scene*. I still can't believe they staged a baptism scene in that river without actually killing their actors. This isn't a Hollywood movie though, and it shows - the pace is slow and deliberate, there's no CGI and it is very downbeat in its message. The female roles are strong and well thought-out while remaining realistically grim.
Online complaints about the sound-quality turned out to be hugely exaggerated. In fact there are only two major flaws. One is the accents; I can cope with Hrothgar sounding Scandinavian and Beowulf sounding Scottish but I cannot cope with a witch with a strong American accent. Why didn't they just coach everyone in a similar Danish accent?
The second flaw was not really their fault: you can spot to the second the exact moment that their finances were whipped out from beneath them, in the last week of filming. It's the fight with Grendel's Mother (who is a monster), which is desperately downplayed but can't disguise the fact they were clean out of cash for her costume.
I enjoyed it and I'd happily watch it again. I think it comes across as an ambitious and very earnest endeavour that almost worked beautifully.
The DVD extras are plentiful and very good too - including a thoughtful interview with Butler about the themes of the film. God he's beautiful. Ahem. Sorry about that...
Oh, and there's a very tempting trailer for their award-winning companion documentry Wrath of Gods (a sort of Icelandic Lost in La Mancha) which details the horrors they went through during filming: blizzards, landslips, waist-deep mud, a director who appears to be a total nutter, a rapidly-closing Arctic winter, financial disaster, ships that could only float for 4 mins before sinking... and finishes with a clip of Butler talking to camera while stripping off his wetsuit. They certainly know their market!
You need to release Wrath of Gods in the UK, guys!
* But they've started commercial whaling again so Iceland is off my holiday list.