Mystery House

Mystery House
1982 re-release cover art
Developer(s)On-Line Systems
Publisher(s)On-Line Systems
Designer(s)Roberta Williams
Programmer(s)Ken Williams
SeriesHi-Res Adventures
EngineADL
Platform(s)Apple II
ReleaseMay 5, 1980
Genre(s)Adventure
Mode(s)Single-player

Mystery House is an adventure game released by On-Line Systems in 1980. It was designed, written and illustrated by Roberta Williams, and programmed by Ken Williams for the Apple II. Mystery House is the first graphical adventure game and the first game produced by On-Line Systems, the company which would evolve into Sierra On-Line. It is one of the earliest horror video games.