What bothers me here is that people claim to program "Minecraft in X lines", when in fact all they create is a block (voxel) game engine. Minecraft is much more than that, it has redstone circuits, farming, mobs, structures, biomes, potion brewing, netherworld, fire, etc...
Mind you, I don't want to belittle anyone's efforts. I think this is an awesome programming project. But its description is misleading.