So I finally got round to playing the demo today - as LoH says, it is rather limited, but unlike previous TW demos, you can at least try out the campaign mode - putting you in control of Chōsokabe Motochika as he extends his power across Shikoku.
I haven't played the historical battle yet (Sekigahara - I'm assuming the player has control of Ieyasu's forces, given the actual outcome), but the tutorial battles I've played so far have been smooth - my machine is just over a year old and can play on 'Ultra' settings without incident.
The campaign system is pretty much the same as normal - only this time, as we've seen, you can actually rotate the map. The campaign interface is very similar in many ways to Empire
- the tax screen, for instance, has barely been altered except for the obvious cosmetic changes.
The Government screen has been merged into the family tree, with the option of promoting your Generals to various positions as Commissioners of War, Supply, and some other roles that escape me at the moment.
And, of course, the demo gives a quick look at the use of Ninjas.
In all, I think Shogun 2 is definitely worth a look - and I say this as someone with very little knowledge about Japanese history, apart from what I learnt the other day from a documentary about Tokugawa Ieyasu, and the little I gleaned from playing Age of Empires II a decade ago.