I wanted to leave a detailed comment on this game earlier, but I felt that I should give it another run through so I could give an honest opinion on it, and now that I have, I'm glad I did.
The few badsides of the game had made me simply forget about the amazing and original game at the core. Okage has an unheard of story, interesting characters, a graphical style reminiscent of The Nightmare Before Christmas, and some well placed humour (if this humour is your style). Now, to add onto the equation, toss in a boring battle system (sometimes you start cursing when you get into a simple encounter wanting to get on with the game) and some of the most repetitive dungeons I've seen in an RPG in a long time, and you still have a worthy RPG, but partially dulled by it's flaws.
The story... but into a short definition is about a kid (well, teenager) who gets "possessed" by a "Great Evil King", and now must go across the world, getting the King's power back and conquering it. Doesn't sound like your usual "save the world" RPG, does it?
Care to know the variety of characters? Well, besides your "Great Evil" posessed boy, you have things ranging from the needed hero, an evil "Teen Pop Idol", a tuxedo clad demon, all the way to a 40 year old genius who stalks young girls/women. Why isn't this kind of variety more common in games?!
But still, there are it's flaws. The battle engine just isn't innovative in any way, it's rather slow, and in turn, rather boring. The dungeons are "destry the urns to unlock the door", but include "unlock different passages to get to urns" that turn some into labyrinth-ish mazes. Now, if there was variety in the dungeons, it wouldn't be that bad, but there isn't. After a few dungeons, you just start dreading them. Then you get put into the 9 level one, and you either cry or turn off your PS2 and walk away for awhile.
Finally, there's not much reason to not just buy this game if you're curious. At the moment, you can find it new for about $10 at many stores, and I'm guessing it's probably near the same on Ebay. So, if you're curious at all about it, don't spend $5 renting it, just go out and buy it. You'll either hate it like some, or love it like me.