I dont get the popularity of this game, I played it on 360 for about an hour and said fukit and traded it in, it was really (imo) quite dire.
I watched full Let's Play and while the combat gameplay does look horrible, the game itself has this weird vibe I find fascinating and refreshing. I always feel bad a little when I use LP instead of actually playing (legal) game and if anything, this PC release means to me that I will be able to express my gratitude for interesting experience and tied the cash to PC.
If KB+mouse controls are any good, I will definitely play it myself.
And it's great that so many people mention DRM-free on Greenlight page. I've already said my piece there.