How do you get the CD code for gunman chronicles?

Answer 1

You have to have the original case that the purchased game came in. There is no universal code or alternative method. Sharing keys is not allowed. Furthermore, the game has been long since discontinued, and is no longer supported. This also means that there are bugs remaining in the original game, and online multiplayer is impossible since the servers are no longer up.

Now, if you're lucky enough to find your box and key, wikipedia.com claims: "...redeeming a Gunman Chronicles CD-Key on Steam gives access to a "Half-Life Platinum Pack" that includes Half-Life 1 and several mods: Blue Shift, Half-Life Deathmatch Source, Opposing Force, Team Fortress Classic, Ricochet and Day of Defeat, but not Gunman Chronicles."

I'm willing to bet they don't allow duplicate keys on Steam, so sharing keys for that also isn't allowed ;)

Hope this helps!