Zork (later called Zork 1) was released by Infocom in December 1980.
By today’s standards, Zork was exceedingly primitive: an Interactive Fiction game where you typed in your commands and the basic language parsing system responded. There were no graphics, no sound, only a screen of text and a score counter. And yet it became an instant classic in computer gaming because it was one of the first immersive games ever made. You felt like you were entering another world, and acting within it. You are about to be eaten by a grue.