I just have to mention the 16-bit ALU implemented in the 3D environment of Minecraft, which has been much discussed by now. I’m glad to hear this game is keeping up with Dwarf Fortress. By the way, the particular piece of hardware that has been (virtually) built, on the way to creating a full CPU, is the one described in The Elements of Computing Systems, a book I wrote about on Grand Text Auto back in 2006.