Released in 1980, Zork I: The Great Underground Empire launched Infocom into almost a decade of prominence in the text adventure game arena. Starting from west of a white house in an open field, you explore the game's underground caverns to find and retrieve 19 treasures, while contending with a variety of traps, puzzles, and a thief who attempts to steal your items. Solving the puzzles by either manipulating the environment or using objects, allows you to progress. A few of the puzzles are ingenious, requiring lateral thinking, or having you determine the best way to transport treasures to a storage area. Most of the puzzles are well designed and quite challenging, and some offer multiple solutions.

The game was originally developed for the PDP-10 computer by a group of hackers at the M.I.T. computer labs. It was simply named Zork, and drew inspiration from Adventure, the groundbreaking text adventure game written by Will Crowther and expanded by Don Woods. When a group of hackers founded Infocom, they decided on Zork as their first product. The PDP-10 Zork was broken up into two parts, with the first part of the game becoming Zork I: The Great Underground Empire. The second half of the original game would be released as Zork II: The Wizard of Frobozz, while some ideas and puzzles that didn't make it into either Zork I or Zork II would be used in Zork III: The Dungeon Master.

Zork I: The Great Underground Empire is an enjoyable and genre-defining text adventure game that's only slightly marred by a pair of tedious mazes, one poor puzzle design, and the lack of a storyline. ~ Kyle Knight, All Game Guide