in metal gear there was a puzzle where you hat to look on the back side of the cd case to figure out a frequency for the radio

is the back side of the cd case included to download ? or maybe even in in an extra section ingame ?

People have said that the answer is in an image for the game on the Store Page

Google it...

It IS the screenshot in the GOG store where he speaks with Meryl. Just input her frequency.

alright ;)

definitely save that picture or write down this frequency if you plan to play offline guys ;)

youll need that later down the road