What made Zork so popular?

Zork became popular because it combined a rich, explorable world with clever writing and a parser that understood more of what players typed than earlier games did. Created at MIT in the late 1970s and released commercially by Infocom in 1980, it let you explore the Great Underground Empire by typing commands, solving inventive puzzles and meeting memorable moments like the grue lurking in the dark. Its sharp, often funny prose and the sense of a real place to discover set it apart when graphics were still primitive, proving words alone could be gripping. Infocom's reputation for quality made it a landmark. Zork helped define interactive fiction, and its descendants still run in the browser on the play page.