Up to the late 90s at least, Metal Gear Solid had a moment where, in order to progress, you had to enter a codec frequency that was in the back of the CD case.
We had a Mickey game that came with a dark maroon piece of paper with a bunch of Mickey poses on it, each one had a number or letter code (it would show a pose and you had to give it the code for the pose to start the game). The black ink on dark maroon paper was intended to prevent photocopying.
We also had this F1 racing game that had a bunch of F1 history in its manual and would ask F1 history trivia to get into the game.
Up to the late 90s at least, Metal Gear Solid had a moment where, in order to progress, you had to enter a codec frequency that was in the back of the CD case.
We had a Mickey game that came with a dark maroon piece of paper with a bunch of Mickey poses on it, each one had a number or letter code (it would show a pose and you had to give it the code for the pose to start the game). The black ink on dark maroon paper was intended to prevent photocopying.
We also had this F1 racing game that had a bunch of F1 history in its manual and would ask F1 history trivia to get into the game.