The Mystery House Advance Team has reverse engineered “Mystery House,” the first graphical adventure game; they have reimplemented it in a modern, cross-platform, free language for interactive fiction development, and fashioned a kit to allow others to easily modify this early game.

“Mystery House” is a primitive interactive fiction for the Apple II by Ken and Roberta Williams, who published the game in 1980 through their company, On-Line Systems (later called Sierra). The game was a hit — Sierra sold more than 10,000 copies sold in a very small, new market for home computer software. “Mystery House” accepts one- or two-word typed commands from the user and presents crude, monochrome line drawings and terse textual descriptions. In 1987, in celebration of Sierra’s 7th anniversary, “Mystery House” was placed in the public domain. The modifiable “Mystery House Taken Over” reimplementation has likewise been placed in the public domain by the Advance Team.