Dwarf Fortress

Dwarf Fortress has levelled up with the big Siege Update out now bringing with it a whole lot of trouble, which should spice things up a bit.

You're not safe in the mountain anymore. Enemies will find new ways to invade by digging, building bridges and overcoming other things like water and lava to get at you. They'll also have new weapons, but you've got some new defensive tricks too. The good news is you shouldn't need to start over for it! However, if you prefer things a bit more peaceful a bunch of it can be turned off too. Sounds like some nice additions to an already deep game.