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 a mission without dying or loading a checkpoint.
Complete a mission using only a pistol and no melee attacks.
Complete the game on the hardest difficulty.
Complete the game.
Finish Berlin.
Finish Rocket.
Finish Hurtgen.
Complete the Russian missions.
Complete the British missions.
Complete the American missions.
Get kills using a pistol, rifle, submachine gun, and grenade in a mission without dying.
Complete Training.