It is done by just a couple of people for 2+ years now. And they got a lot to show for it. You can check out a couple of gameplay trailers on youtube.
But all the most important questions can best be answered by the developers themselves.
So head on to their kickstarter page to learn all you want to learn and please support them: http://www.kickstarter.com/projects/crateentertainment/grim-dawn
This game when it is done will be the aRPG dream come true!!