They were a team with a plan. Im sure all serious gamers here have thought about making that perfect game with all these cool features that would be totally awesome, in theory. These guys have showed us the game they want to make, but demonstrated that they are serious about it. even if it sounds totaly cool, they think about whether it actually works or not.
On top of that, they have found a theme for there game. All of the best games out there, no exception, have a particular feel to them such that its like art, without all the finger painting. (Ok so i dont really get art) If all the finishing touches are as good as the fan made music or better, this game will suck me into the world they create. And i feel that its the ability of the game to draw you into its world that makes a good game, great.