From their website:
Here is a look at the cover to the Core Rules book. Attendees at PAX East and GAMA will get a first hand look. Also anyone at PAX East who participates in a Rumble there will get a free copy of this 48 page preview. The Limited Edition Preview is the complete Core Rules to play the game. Sadly it is only Con exclusive, but is the harbinger to the eventual release of the rules themselves.