I just finished this game today, with a total of 63 hours gameplay. This is amazing considering most games these days have an average of 12 hours gameplay, so more than worth the money. Furthermore, this 63 hours of gameplay isn't just the same old repetitive junk some games are designed to spew out. This game has an intense story line, and every time you think the game may be ending a new chapter emerges.
There are several characteritics to this game which make it truly unique and awesome. The 'celestial brush', the soundtrack, the multi-layered characters etc. But my favourite aspect by far is the amount of detail put into the myth and legend aspect of the game. Almost every aspect, from the gods, the way they behave, the heroes, storylines, 'the wandering artist', the cultural references, everything has some inspiration in true Japanese myth.
Combine that with the graphical style of Japanese woodcarving and watercolours which provide the inspiration, then you get a truly stunning experience (just watch any trailer).
And in true RPG spirit, there are a number of side quests, collectables, power-ups. The designer for this game took a lot of inspiration from the Zelda games, so if you find yourself enjoying them then you will probably like this game.
In summary: Epic!