Fantastic Four

Hidden options:
Highlight the "Training mode" selection on the options menu and press L1 + L2 + R1 + R2. Additional options, including invincibility and stage skip, will now appear.

Stage select:
Enable the "Hidden options" code and activate the stage skip option. Then, press L1 + L2 + R1 + R2 during game play to display the stage select menu. Press Up or Down and press Triangle or X to select a new stage. Then, press Start to resume game play at the selected stage.

One hundred lives:
Press Up(2), Down, Left, Right, Down at the title screen.

Same character game:
Start a two player game. Press Start, Select, select a new character and press X. While the new character appears in the blue ray, quickly press Start, Select on the other controller. Both players should now be playing the same character.