The code wheel was necessary to access the PAX terminals in the game at certain points and without it, the player hits a dead-end in the plot. When the player use the PAX machine, there are given three access codes and game asked for a verification code.
This is scan of Commodore 64 version (US release) of Neuromancer - PAX Verification Code Wheel
Thanks to ~ Steverd from www.c64copyprotection.com ~ for codewheel source scans.
The game is loosely based on the events of the novel Neuromancer by William Gibson. Locations, characters, items and nuances of cyberspace from the novel appear.
Taking place in the year 2058 in Chiba, Japan, the plot centered on the protagonist attempting to discover the truth behind the mysterious disappearances of his friends as well as other, less friendly cyberspace cowboys. Unfortunately, the player's character has fallen on hard times and has had to pawn his cyberspace deck. He awakes in a plate of Ratz' famous spaghetti, and the first order of business is to find some way to retrieve his old deck from the nearby pawnshop.
After obtaining the deck and upgrading the software to enable cyberspace access, the character finds that users of the Matrix are being killed or flatlined by a group of AIs led by a renegade named Greystoke. After destroying Greystoke, the player meets Neuromancer who explains that he has manipulated the player into killing the other AIs, and traps him on a virtual island (as in the ending of the book). However, the player can use their skills to escape and destroy Neuromancer, making the Matrix safe again.
Some other aspects of the book are included in the game as red herrings. For example, the character Armitage can contact the player at one point, but if the player accepts his mission, he and Armitage are immediately arrested.