May 2020 marks 40 years since the release of the groundbreaking adventure game Mystery House, written by Roberta Williams and programmed by Ken Williams, the founders of Sierra On-Line. By their own reckoning, the entire development took place in about three months, leading to a self-published release in May 1980 through Micro Magazine. It is considered the first graphical adventure game, using an early form of vector graphics to fit the game onto a 5-1/2" floppy disk.
I would like to point out that Roberta Williams developed the concept, wrote the game, and created all of the art while working as a stay at home mom with two children under five years old. For those of you with kids at home right now, I'm sure you understand what an heroic undertaking that was.
Playable copy of the game on the Internet Archive:
Hi-Res Adventure #1: Mystery House