Microsoft has released the original Zork trilogy code under MIT licence, unlocking a defining piece of game-development history for educators, indie developers and retro-gaming communities to study, use and preserve.
Microsoft has officially open sourced the complete source code of the iconic Zork trilogy, Zork I, Zork II and Zork III, marking a landmark move in gaming preservation. Released under the MIT licence, the repositories now provide broad rights for access, reuse, modification and redistribution, provided copyright notice and licence text are retained.
The updated repositories include source code, build notes, developer comments and documentation, enabling deeper exploration of the engineering behind one of the earliest and most influential text-adventure game systems. Licensing exclusions apply to trademarks, commercial packaging, marketing content and any non-code assets such as graphics or sound.
Developed in the late 1970s and early 1980s by Infocom co-founders Tim Anderson, Marc Blank, Bruce Daniels and Dave Lebling, Zork pioneered the Z-Machine — a virtual machine enabling the same game to run across diverse early microcomputers. Microsoft gained the rights through its 2023 acquisition of Activision Blizzard.
This move resolves long-standing ambiguity: earlier archival uploads lacked formal open-source permission. Now, Microsoft has officially relabelled the code under MIT via upstream pull requests, unlocking legal reuse worldwide.
Microsoft stresses this release focuses on cultural preservation rather than remasters. One industry commentator said the aim is simple: “our goal is simple: to place historically important code in the hands of students, teachers and developers so they can study it, learn from it, and, perhaps most importantly, play it”.
Developers highlight the educational value of the Z-Machine — described as “a marvel of portability”, and note that “this code is mostly in ZIL, which is compiled to Z-code”.
With build instructions and support for tools like the ZILF compiler and Frotz interpreters, a new wave of academic study, modding and retro-gaming innovation is now fully enabled.
