An unnamed adventurer enters the Great Underground Empire to recover twenty hidden treasures while navigating a labyrinthine environment. The protagonist must manage limited inventory space and light sources while solving environmental puzzles to progress through the subterranean ruins. The narrative is delivered through a text-based parser interface, requiring the player to input commands to interact with the world and overcome obstacles. The environment operates on strict logical rules where specific items are required to bypass hazards or unlock new areas.

Discussion often centers on the technical achievement of the parser in simulating a complex environment within the memory constraints of early computing hardware. Readers and players frequently highlight the challenging nature of the puzzles, which require careful observation and logical deduction. The atmosphere is often described as stark and immersive, relying on descriptive prose to build a sense of isolation in the underground setting. Many critics note that the game established the conventions for the interactive fiction genre, influencing decades of subsequent narrative-driven software design.