Zork: The Great Underground Empire - Part I, later known as Zork I, is an interactive fiction computer game written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson and published by Infocom in 1980. It was the first game in the popular Zork trilogy and was released for a wide range of computer systems, followed by Zork II and Zork III. It was Infocom's first game, and sold more than 400,000 copies.
The game takes place in the Zork calendar year 948 GUE (although the passage of time is not notable in gameplay). The player steps into the deliberately vague role of an "adventurer". The game begins near a white house in a small, self-contained area. Although the player is given little instruction, the house provides an obvious point of interest.
When the player enters the house, it yields a number of intriguing objects: an ancient brass lantern, an empty trophy case, an intricately engraved sword, etc. Beneath the rug a trap door leads down into a dark dungeon. But what initially appears to be a dungeon is actually one of several entrances to a vast subterranean land—the Great Underground Empire. The player soon encounters dangerous creatures, including deadly grues, an axe-wielding troll, a giant cyclops and a nimble-fingered thief.
The ultimate goal of Zork I is to collect the Twenty Treasures of Zork and install them in the trophy case. Finding the treasures requires solving a variety of puzzles such as the navigation of two brutal mazes and some intricate manipulations at Flood Control Dam #3.
Placing all of the treasures into the trophy case scores the player 350 points and grants the rank of "Master Adventurer." An ancient map with further instructions then magically appears in the trophy case. These instructions provide access to a stone barrow. The entrance to the barrow is the end of Zork I and the beginning of Zork II.
It is possible to score all 350 points in 223 moves (and win the game completely in 228 moves) by exploiting a bug.