What Keeps Dwarf Fortress Evolving for 20 Years? Inside a 700k‑Line Solo Project

If you ask which computer program can be called the most epic ever, Dwarf Fortress certainly makes the list. Released in 2006, the game pioneered the idea of defining core rules and letting the world and players discover everything else, a concept that even inspired Minecraft’s creator.

The entire project has been built and maintained by a single developer, Tarn Adams (aka Toady One), who has been coding nonstop for 20 years; the codebase now exceeds 700,000 lines.

Natural Growth Over Two Decades Without Refactoring

Adams, a former university math professor, quit his job in 2002 to work on the game full‑time. By February 2020 the latest update was version 0.47.05, meaning the game is 47% complete according to his progress‑based versioning.

Dwarf Fortress offers three inter‑linked modes: Fortress building, Adventure (a roguelike), and Legends, each influencing the others. The world is rendered entirely with ASCII characters, giving it a distinctive, surreal look.

Adams programs the game mainly in C and C++ using Microsoft Visual Studio (now the Community edition) with OpenGL and SDL as the engine. He rarely uses external libraries, relying only on a few random‑number generators such as Mersenne Twister and SplitMix64.

The original code from 2003 is still the foundation; the project has seen virtually no major refactoring, with only occasional structural tweaks over the years.

Funding comes entirely from player donations via PayPal, amounting to a few thousand dollars per month, enough to cover Adams’s modest living expenses.

Adams has consistently refused commercial offers and publishing deals, believing that monetization would compromise the game’s long‑term development rhythm.

Personally, he lives frugally—about $860 a month for rent and minimal other costs—and follows a rigorous daily schedule of coding from early afternoon until early morning.

Health challenges, including his brother Zach’s cancer diagnosis, prompted Adams to launch a Steam version in 2019, providing a crucial revenue stream to cover medical expenses.

Future updates aim to add AI‑controlled villains with their own motives, expanding the game’s narrative depth across all modes.

The game’s influence is evident: it has been featured in the Museum of Modern Art and continues to inspire developers worldwide. As long as health permits, Adams and his brother plan to keep updating Dwarf Fortress, embracing the mantra “Develop until death, never stop updating.”