Underground

Zork is a text-based adventure game wherein the player explores the ruins of the Great Underground Empire. The player types text commands for their character to traverse locations, solve puzzles, and collect treasure. The game has hundreds of locations, each with a name and description, and the player's commands interact with the objects, obstacles, and creatures within them. Commands can be one or two words (e.g., "get lamp" or "north") or more complex phrases (e.g., "put the lamp and sword in the case"). The command must fit the location's context (e.g., "get lamp" works only if a lamp is present). The program acts as a narrator, describing to the player their location and the results of certain actions. If the game does not understand the player's commands, it asks for the player to retype their actions. The program's replies are typically in a sarcastic, conversational tone, much as a Game Master would use in leading players in a tabletop role-playing game. The original 1977 version of the game was a single release, Zork. When it was converted into a commercial software title, it was divided into three episodes, with new and expanded sections added to the latter two episodes. Much of the game world is composed of puzzles that must eventually be solved, such as a set of buttons on a dam or a maze to be traversed. Some puzzles have more than one solution. For instance, since the "Loud Room" is too overwhelmingly loud for the player to perform actions, the player can either empty the nearby dam to stop the sound of water falling, or shout "echo" in the room to change its acoustics. In the first episode, or Zork I, a thief character is wandering the underground as well, taking items that have been left behind or even stealing from the player's possessions. The player can fight or evade the thief, and can recover stolen items from the thief's treasure room. Some locations contain antagonists that the player must fight or overcome. Beginning in Zork II the player can learn magic spells to use in puzzles and combat. In dark areas, the player must carry a lantern or other light source to avoid being eaten by a monster called a grue. There is a limit to how much "inventory" one can carry, determined by the combined weight of objects, rather than the quantity. A principal goal of each episode is to collect all the treasures, many of which are hidden behind puzzles. As treasures are collected or tasks are accomplished, the player's score increases, providing a rough measure of how much of the game has been completed. The player may traverse the game world and solve puzzles in almost any order, although some passageways require problem-solving to get through, and some puzzles require the player to possess something gained from solving a different puzzle. In Zork III, unlike in prior episodes, there is a timed component that directly affects the outcome. An earthquake will occur after about 130 moves, opening one passageway and closing another. In each episode, the treasures are needed to reach the conclusion of the game.