Huygen's Disclosure is set in 2020 when the ozone layer is almost completely destroyed. A member of the Galactic Reconaissance Unit is sent to the moon Titan to examine if the recently found gas Rachellium could be the solution to earth's environmental problems. But of course he gets immediately involved in the resident's own problems.

The player character is controlled with the mouse. When pressing a key on the keyboard the game opens a menu were the four main options can be chosen. The adventure part consists of logic puzzles like the assembling of a broken solar cell, finding and using inventory items and multiple-choice conversations.

The second part of the game is the combat with the various life forms of Titan. Instead of a point & click interface the player has to use a aiming panel on the upper right corner. By moving a crosshair inside this box the player aims his weapons in the actual game world. The weapons are fired with the already mentioned menu. During the game the player meets companions which help him during combat. They also receive their orders over the keyboard menu.