The NPCs, for example. While you couldn't say they were more 'well-rounded' exactly - in fact, far from it, they're nutters - Bethesda admit that their Radiant AI system wasn't used to its full potential in the main Oblivion quests; this time they've been given a blank cheque for mayhem, with the smaller world and way-out setting enabling them to create some truly unforgettable characters.
And then there's just the feeling that this is the world Oblivion should have been; a gloriously discordant, unsettling destination that really jolts the old imagination glands. When that first dingy room fades away in a shower of butterflies and you cast your eyes on this bizarro world, you'll feel like you've been invited to the Mad Hatter's tea party - and you're the main course, naturally.
Ultimately, however different it is, it is still just Oblivion, of course, and those that don't get into hot flushes at the thought of a 15-hour quest to retrieve the Sacred Spanish Potato won't find anything here that'll change their minds. But it's far-out enough and inventive enough to be more than worth a look, even if you think you're sick to the back teeth of goblets and axes and murderous skele-men and the like. Forget the whole horse armour debacle - Bethesda have managed to create another gorgeously explorable land that's well worth your money. We'll have a full, proper review in June.