Tired of waiting for the Natsume and Taito logo to disappear when you start up your Bust-a-Move 4? After the game loads from your memory card in the beginning, do a soft reset (Start+Select+L1+R1) and you will be taken to the Title Screen without seeing the Natsume/Taito logo.
At the original title screen, press Triangle, Left, Right, Left, Triangle. A small character will appear on the bottom left side of the screen. Then, go into Puzzle Mode and choose Arcade to access a new set of puzzles.
At the title screen, where it says "push start" You will enter this code: left, left, triangle, right, right, triangle, left, left.
To gain access to five new characters, beat Story mode in Player vs. Computer mode. Doing this gets you Madam Luna and Dreg.
After that, play Win Contest mode until you fight a new character. Beat them, and they are yours!
At the title screen, enter this code: Square, Up, Left, Down, Right, Up, Square, Down, Left, Up, Right, Down, Square.
*NOTE: you will need to have the extra characters and tarot readings for this code to work
On the title screen, where it says "push start button" enter this code: Up, Triangle, Down, Triangle, Up. You'll hear a noise, that means it worked.