Minecraft has become an insane success story for the Swedish and Nordic indie games community. The game began alpha development in 2009, and shot up in popularity in part due its open style of play and creator Markus Persson’s constant interaction with its vocal community. After hitting 4 million total sales this week, Minecraft (as opposed to Minecraft Beta) will be released sometime during their convention, Minecon, two weekends from now in Las Vegas.

Mojang, the company founded about a year ago after Minecraft’s success, has recently grown to 12 people with three more signed up. Aside from an Xbox 360 port to be released in 2012, they are also developing a game called “Scrolls” which features board game and card collecting elements.

It’s difficult to describe what makes Minecraft fun to someone who hasn’t played it, partially due to the many directions you can take the game. Your character lives in a world of easily movable and removable blocks, which you can use like simple Lego bricks to build structures. And when nightfall comes, monsters come out of the woodwork for you to fight or run away from, which also give some purpose to your structures.

Image from GameReactor.fi

Recently Minecraft has included populated villages for you to interact with, a need to eat food, and a separate creative mode where you can fly around and build structures with infinite blocks.

Currently over 4 million people have puchased the game, making it competitive with hits from established game developers. Within the past 24 hours of this article’s writing, 48,052 people registered and 9,966 people bought the game. When we covered Minecraft’s win of the GDC 2011 conference last March, they had only 1,470,357 purchases. Minecraft’s basic stats are publicly available here.

Here’s the trailer on the Minecraft website if you need to get a better feel of the game: