According to the website there will be 4 demos available... Going by their website...
Pikmin 3, Wonderful 101, Super Mario 3D, and Wind Waker HD. If so, I'll be mildly disappointed. Not too psyched to try Pikmin or Wind Waker HD. Not that I'm not looking forward to those games, but I've played through WW several times, and Pikmin 3 is pretty much a known quantity. Kind of excited to try Wonderful 101, and Mario 3D is the game I want to play most of all.
Of course, they could just be using these silhouettes to avoid showing off the more surprising titles. Personally, I'm hoping the demos will be... Mario 3D, Smash, Retro's Next, and Sonic Lost World.