Released in December 1980, Zork: The Great Underground Empire – Part I aka Zork I was an interactive fiction video game written by Marc Blank, Dave Lebling, Bruce Daniels and Tim Anderson and published by Infocom.
Upon starting the game the player is informed that the game takes place in the Zork calendar year 948 GUE and that the player is an adventurer. A white house then appears that must be investigated.
Upon entering the house the player discovers numerous objects of interest that include a brass, battery-powered lantern, an empty trophy case, and an Elvish sword of great antiquity. Beneath the rug a trap door leads down into a dark cellar, which is revealed to be one of several entrances to a vast subterranean land known as the Great Underground Empire.
The player soon encounters a colourful host of dangerous enemies, including deadly grues who only prey on their victims in the dark, an axe-wielding troll, a giant cyclops who flees in terror at the mention of Odysseus, a vampire bat that can drop the player anywhere in the mine if encountered, evil spirits guarding the Entrance to Hades, and a nimble-fingered thief who makes mapping the maze difficult by removing or scattering any items that the player might drop to leave a trail.
The ultimate goal of Zork: The Great Underground Empire – Part I is to collect the Twenty Treasures of Zork and install them in the trophy case.