I used to have all kinds of them from the Game Software Code Creators Club, but the site has since disappeared and I chunked the codes since the game is incredibly easy, and they didn't help with what I needed (to find caps of each character).
But yes, they were all single player codes.
"I will... ... ...never be a memory..." - Sephiroth (FFVII:Advent Children)
It's better - BUT this is a perfect illustration of how quickly things can change. Look at what happened to GS Central after it got hacked. They got so scared that they changed the format of the site to where it's completely useless now. Codebreaker could be gone just as quickly.
There are few things more disturbing than waking up in the morning, only to discover that you are dead for the rest of your life.