I'm not sure on that. I believe that the code the angel gives you is simply the final password. There's a secret code that allows you to play the intro stage (the place that looks like the arew where you fight the final boss in Final Fantasy VI) but I don't know where they give it in the game.

I'm beginning to think they simply don't give it in the game, and you just have to get if from a magazine or the internet or something.