Unfortunately none of those demo links on the Kickstarter page works anymore. The ones hosted by Atomicgamer are all corrupt. I have downoaded it through each of their mirrors at least twice, it took about 4 hours and not one of them worked.
I guess I will wait until a new demo is released.
EDIT: Okay, tried once more and finally the file was not corrupted this time. Have played about 4 mins and looks good, will give it a better try in the morning. Better get to bed since it is about 2am here, haha.