The game is a sandbox game in which the world is made up of block units, all of the same size. Units can be dirt, sand, stone/cobblestone, and various ores. The

The game is a sandbox game in which the world is made up of block units, all of the same size. Units can be dirt, sand, stone/cobblestone, and various ores. There are trees as well, and combining various raw materials, you craft progressively more complex things. From there, you can build almost anything granted you have the resources. In survival mode, there are zombies and spiders that appear at night. They're pretty difficult to kill with just your hand, and they will mob you pretty quickly. So you essentially have to construct a safety fort to live. People solve this problem in pretty elaborate ways sometimes. One of the most interesting aspects of the game is how subtle the world around you is. When you cut down a tree, you usually can find a new tree seed to plant it again. The tree grows based on how much light it's exposed to. The zombies sometimes get in fights with each other, or local non-violent wildlife (pigs, cows). Water can flood your tunnels if you hit it, and lava does the same. All of this, and it's endearing. The menu screen has a joking catchphrase which changes every time, the developer Notch is as in love with the game as everyone else, and the rest of the community is hugely cooperative in building things, even if it takes a huge amount of effort. These reasons are what get people to stay, and get the purchase. I only wish I could hack on this code, the problems seem hugely interesting (rendering miles of block, even at low detail, is resource intensive, and simulating an environment on top of that).