I dont understand why they dont just give out the demo for everyone, by putting it on the eshop.
But thats nintendo for you. Always late and off by some feet.
They really need to get better, there falling behind.
It's because the only demo they have right now (the E3 build) is unstable and is prone to glitches or crashes, like any other E3 demo. It wouldn't be a good idea to release it like that.