You are Captain Kelly, a space delivery man who travels the universe delivering packages, an easy enough job until you came across the ship, Obsidian 2. Normally a code would shut down the security and hand control back to the pilot but today the code wasn't working and you made the mistake of entering the ship and now you can't leave and the security robots will try to kill you if discovered. You must explore and destroy a set number of robots on each of the seven levels of the ship before entering the Master Control Room and gain full control of the ship.
The game is a top view maze game with the screen scrolling when you move. As you move about each level there are robot guards and you can shoot them with your gun but this has limited ammo. If you touch a robot or are shot then you lose part of your energy and you also have a limited supply of oxygen which counts down and if your energy or oxygen runs out then it is game over. Scattered around the various levels are places and items that increase your energy, oxygen or ammo with teleport's taking you to other levels of the ship. Terminals used will give you updates on your progress as well as how many robots need destroying on each level.
Once you destroy the last robot needed on each level, this will shut down everything on that level including the items needed to increase your energy, oxygen and ammo but teleport's still work. When all robots needed are destroyed, you may enter the Master Control Room and attempt to power up two satellites within a time limit to complete the game. A joystick is used to control your hero.