Zork: The Undiscovered Underground

Zork: The Undiscovered Underground (or ZUU for short) is an interactive fiction computer game written by former Infocom Implementors Marc Blank and Michael Berlyn and implemented using the Inform language. The game was released by Activision on August 28, 1997 for free to coincide with the release of Zork Grand Inquisitor. ZUU can be seen as having two goals: promotion of the commercial title Zork Grand Inquisitor, and an attempt to reconcile with die-hard Infocom fans who may have harbored resentment against Activision for their role in buying Infocom in 1985 and subsequent closure of the company in 1989.

Plot
Zork: The Undiscovered Underground, a prequel to Zork Grand Inquisitor, is set in the year 1066 GUE. The game is played from the viewpoint of your character who is a private in the Inquisition Guard, tasked with exploring a recently discovered area of the Great Underground Empire. The game merges classic "Zorkian" references such as grues and zorkmids with elements created for the newer game, such as the Grand Inquisitor.

The purpose of the game is to explore and emerge successfully from the Undiscovered Underground. The player begins only with a low-quality Lantern and plastic imitation sword, a parody of the starting items from Zorks I, II and III. Upon entering the Undiscovered Underground, the adventurer is trapped by a freak avalanche. The only way to escape is to release the mutant Rat Ants (an echo from Starcross) and to direct them to the avalanche, which they dispatch in a manner reminiscent of Aesop's Fables. The player must demask the Grue vendor to gain the four candy bars and place the relevant objects in the Mud Forum on the appropriate corresponding floor symbols. This unleashes a mutant chase reminiscent of Planetfall where the adventurer stays one step ahead of the Rat Ants because of the shrewdly placed candy bars. However, the escape comes at the cost of unleashing a Rat Ant epidemic onto the empire and forces the adventurer to flee from the wrath of the Grand Inquisitor.

Alternatively, the player can solve the remainder of the puzzles for a slightly happier ending. Attaching the tinsel hidden in the tree in the Mud Forum to the zorkmid hidden in the trunk backstage allows the player to dupe the Implementers (named after the creators of the game) in the Museum of Illusion into revealing several hints. With the newfound information the player can use the clothes in the Changing Room (any matching combination works) to penetrate the Grue convention in the Convention Hall to obtain the glasses. The glasses can be combined with the coloured lenses on the Stage to decode the image in the Mud Forum (which allows the adventurer to order the objects without using guess and check). However, the Implementers also tell the adventurer which rib of the skeleton in the Museum of Adventure to pry. The low-quality sword snaps if the wrong rib is attempted, and the correct rib (which varies from game to game) does not exist until the adventurer is tipped off by the Implementers.

Prying the rib gives the adventurer access to the Janitor's Closet, a room of global proportions that contains a spray can whose contents allow the adventurer to defeat the Rat Ants, earning an afternoon off from the Grand Inquisitor.