The game is set on the titular space station located within the centre of an asteroid, which is out of control and drifting towards a black hole.

The player must guide an astronaut with a jet pack around the station and re-activate its engine shields to prevent the Obsidian's destruction.

Players control a jet pack wearing astronaut who must deactivate the five engines of the titular spacestation Obsidian, which is located in the hollow centre carved out of an asteroid.

[1] The game world is filled with traps, laser defence mechanisms and security robots, all of which kill the astronaut on contact, resulting in the loss of one of his five lives.

These defences must be shut down with objects obtained from gravity boxes in order to progress,[1] as the player has no weapon to directly attack the robots with.

The Obsidian's internal systems are capable of withstanding the black hole, but the station cannot shield its human inhabitants from the gravitational forces.

The crew have taken refuge in a smaller craft which has been shielded, intending to return to the Obsidian when both vessels have passed through the black hole.

[4] A radiation storm has damaged the Obsidian's engine protection systems and erased its flight path, leaving the station drifting towards the black hole where it will be destroyed.

Only one member of the crew has the skills necessary to return to the Obsidian and prepare it to pass through the black hole, this is the game's player character.

Wade stated "...as the playing area opens up it soon becomes clear that many objects will be required to complete the game and that some hard thinking as well as trial and error will be needed."