Unlock ALL Characters and Cutscenes: At the Options screeen go to Gallery and highlight the Cutscene Viewer and hold X and press Up, Down, Left, Right.
Unlock Character Select in Endless Puyo Pop: Go to the Main menu and go to Endless Puyo Pop. Highlight the course you want then press Up, Down, X, A. If the code has been entered correctly You will hear a confirmation sound. You can now can play as any character in Classic mode. To change this hold down the X button and then pick a character at the character select. This will give you their Puyo set.