Professor Elvin Atombender, well known computer genius and psychopath, has hacked into the military computers of the major nations.
Within six hours he will have deciphered the launch codes and started world war three. This is how long you are allocated to penetrate his underground stronghold and find the control centre.
The professor's hideaway is a 32 room complex criss-crossed by a net work of lifts and it is in one such lift that your mission begins.
Exits to the left and right can be explored or you can press the down key and the lift will descend to the next level.
Your footsteps echo as you leave the lift and run along the corridors - running off the screen causes the adjoining room to be displayed. This is made up of a series of catwalks, some of which can be accessed using mini lifts.
All the rooms are patrolled by the professor's robots which are sensitive to movement and armed with high voltage electrodes.
Using the lifts in the correct sequence will help you to avoid most confrontations with the metal menaces. When an encounter is unavoidable you must rely upon your athletic prowess and split second timing to somersault over the approaching robot.
To enter the professor's control room you need a nine digit code, doled out a digit at a time as you complete a series of sub-puzzles. Puzzle sections are hidden in the furniture to be found in each of the rooms, as are passwords which can be entered into any of the professor's security terminals.
You search the furniture by standing in front of it and pressing the down key. A searching indicator is displayed, and you keep your finger on the key until the bar reaches zero.
At this point you will be told what you've found, but quite often you won't find anything.
All rooms contain at least one security terminal. Accessing this will enable you to immobilise the robots for a while or reset the lifts to their original position.
Impossible Mission is a very good conversion from the Commodore original.