PS1 | Submitted by GamesRadarExtra Lives
Using Adventure mode press Start to pause the game. Now press L1, L1, L2, L1 and press Start to return to the game. To get extra lives just press start to pause the game and Right for the extra life.
Dreamcast | Submitted by VatoLoco79"Get a life" and "All levels"
While playing in any level press and hold A,B,X,Y and L,R and the game will appear to stop. Now, while still holding all the buttons as shown above you can move the joystick up and "get a life" will appear on the screen giving you more lives or you can move the joystick down and "all levels" will appear. Now that you have "all levels" showing on the screen release the buttons and now press the start button and you will have your choice of any level to play.