Dynasty Warriors (Playstation): Unlock All Characters

The Substack Rings of Saturn is a good place to look for secrets, they use reverse engineering techniques to find undisclosed and undiscovered codes. One recently found, believed to be hitherto unpublished, unlocks (nearly?) all the characters for Dynasty Warriors on Playstation. From Character Select, it is Up, Down, Down, Right, Right, Left, Down, Square, Circle, Up, Up, Triangle.