Full list of all 12 Call of Duty Classic achievements worth 200 gamerscore. It takes around 15-20 hours to unlock all of the achievements on Xbox 360.
Complete the American missions.
Complete the British missions.
Complete the Russian missions.
Complete the game on the hardest difficulty.
Get kills using a pistol, rifle, submachine gun, and grenade in a mission without dying.
Complete a mission using only a pistol and no melee attacks.
Complete a mission without dying or loading a checkpoint.
Complete the game.