Shinobi's 3DS outing will have Streetpass functionality that brings extra challenge gameplay to the table. It's all detailed in the above trailer, which helpfully spells it all our for us. Good going, SEGA!
I was encouraged by what I've played of Shinobi, but I'll need to get hold of the whole thing before I'm fully confident. I used to adore the old Shinobi games, so I'm definitely keeping my fingers crossed.
\ We've blogged about this before: read (3) back stories