Based on what Mercer has said on the matter of maintaining ownership of his ideas. I think that chance was ended roughly when The Escapist took full control of There Will Be Brawl.
Base mechanic is 2d12 for most rolls. One of which is the hope die, and the other the fear die. You add the numbers together and say which die was higher to determine the result.
I think you're misreading the average damages (to the third decimal point) as total. Nydas did 319 damage over 4 episodes, for an average of 79.75 damage per episode.
Some of Spenser Starke’s tweets on the game make it seems like it was a design goal of his to both introduce a primarily D&D playing audience to FitD and also to bridge the gap between them to soften the transition some.