It's stated on the FAQ Page that he plans to port it to other OSes.
My guess is that he will use the Monogame framework. It's the open-source continuation of XNA.
I don't mind minecraft clones... if they bring anything new.
Like Blockscape's sculpting blocks or Blockade Runner's space theme.
...they could get better names though.
I think it's to early to tell. As it is right now it seems less fun than minecraft. The graphics are impressive but I wonder what kind of cpu power a voxel based game that detailed would need. And as the article says, it looks weird and sometimes just ugly. We'll see.
EDIT: I watched what's on their website and I'm getting used to the look. The blocks still look strange but the organic sculpt tool and the organic shapes look wonderful actually. I think the developer shouldn't try to make it too much of a minecraft clone and make the sculpting standard for natural materials and the blocks only for bricks and stuff. Maybe he'll do that. He seems pretty good. I downloaded the demo (woohoo), can't wait to play it.