Jojo's Bizarre Adventure Cheats

Unlock Dio:
Highlight "Alessy" at the character selection screen and press Start. Highlight "D'Bo" and press Start. Highlight "Chaca" and press Start. Highlight "Milder" and press Start(3). A hand and pencil will draw Dio's icon if you have entered the code correctly.

Unlock Shadow Dio:
Unlock Dio, then highlight him and press Start(10).

Unlock Young Joseph:
Highlight "Jotaro" at the character selection screen and press Start. Highlight "Polnareff" and press Start. Highlight "Joseph" and press Start. Highlight "Kakyoin" and press Start. Highlight "Iggi" and press Start. Highlight "Avdol" and press Start. Highlight "Joseph" again and Young Joseph will eventually appear.