Codebreaker , released in 1978 for the Atari 2600, is an Action & Adventure game where your goal is to guess a secret code generated by either the computer or another player. Depending on the difficulty setting, you have either 8 or 12 chances to figure out the code by entering values with the keyboard controller. After each guess, the computer analyzes your input and displays results indicating if you have a correct digit in the correct position, a correct digit in the wrong position, or no correct digits at all. Points are scored based on how many turns it takes to correctly identify the code. A second game variation called Nim is also included.
The gameplay involves using the keyboard controller to input values and trying to guess the secret code. The computer provides feedback after each guess, helping you narrow down the possible combinations. You must use this information strategically to increase your chances of winning. Alongside Codebreaker, Nim is also included as a second game variation, where players take turns removing items from a stack until one player wins or loses.