Erm. It's mostly a minecraft clone originally based on Pixel Perfection texture pack which was open source licence, but is increasingly getting more of it's own art, and some unique features. Burgers to lure villagers for example. I was told bookcases that stored books was in the MineClone2 first. It's a pretty solid game and very playable but certain parts still need to be implemented. Redstone is not quite where it needs to be yet. Mobs are progressing, but need a little work still, but for a FOSS game on a FOSS engine, you cannot go better! :)
I was impressed by how much content and how playable it was, and it goes from strength to strength.