In their youth, the Adams brothers were avid fans of sci-fi and fantasy games. They became curious about computer game development and Tarn worked to learn programming. The two programmed various computer games including "Slaves to Armok: God of Blood", a role-playing game focused around killing goblins. Using much of the system created for "Armok" and inspiration from their mining game "Mutant Miner", they began work on "Dwarf Fortress" in 2002. The game has been in development since 2006, with frequent updates on progress and planned features. The game is free to download and its development is funded through PayPal donations.