Dwarf Fortress is a single-player fantasy game. You can control a dwarven outpost or an adventurer in a randomly generated, persistent world. The world is randomly generated with distinct civilizations spanning over 1000 years of detailed history, dozens of towns, hundreds of caves and regions with various wildlife. Command your dwarves as they search for wealth in the mountain. Play an adventurer and explore, quest for glory or seek vengeance. Extended ASCII character set rendered in 16 colors (including black) as well as 8 background colors (including black). Although Dwarf Fortress is still in a work in progress, many features have already been implemented. Please post all support issues in the forums for the game.
Complexity and accuracy (within reason, and to a level that can be achieved with cubic meter blocks) coupled with a completely randomised worlds chock full of individual history and unique lore and beasts makes an extremely immersive gameplay possible -- even with only text! Fortress mode challenges you with logical and strategic gameplay, where Adventure mode takes you out of the group and sticks you with a single mercenary, able to travel the whole world and do what you wish, focusing on intense turn-based battles and personal fame.
The community makes the game twice as good as it could be, with tales and legends, challenges being issued, and of course a plethora of mods to help you meet your goals without coming out completely fried by the complex userface.
And the best thing is, it can only get better from here on out!