The Game: You find yourself outside an inviting two-story house, and when you go in, you find several people waiting for you – and that inviting front door suddenly locked behind you. When dead bodies turn up on the second floor and night begins to fall (hope you found the matches in the cupboard already!), it quickly becomes apparent that among the friendly faces of the first floor is a cold-blooded killer. (On-Line Systems, 1980)
Memories: The very first game released by a new company formed by husband-and-wife team Ken and Roberta Williams, Mystery House is the first in a series of “Hi-Res Adventures” combining simple graphics and text descriptions and actions. The “Hi-Res Adventures” series would grow to include titles licensed from Disney and the Jim Henson Company, and would even survive the Williams’ company’s transformation from On-Line Systems into Sierra On-Line.
Roberta Williams has said on several occasions that Mystery House can be considered the first computer game whose graphics depict specific scenes in the game, rather than just abstract avatars for the player(s) themselves. (In that respect, however, it seems as though Mystery House is almost neck-and-neck with Akalabeth, released at around the same time.) In both cases, the graphics are primitive B&W wireframe line drawings created in the Apple’s hi-res mode, and that lo-fi look has its own charm and humor in retrospect.
On the downside, gamers weaned on more modern fare will probably find the pacing to be incredibly slow, and the text input parser isn’t even up to an Infocom level – but counting off 
points for the former would be like taking points off from a minor B&W silent movie classic for not having Dolby 5.1 surround. Though the show-and-tell architecture that Mystery House introduced to computer adventure games has come and gone, it was still an important step in the evolution of that genre.