At the title screen, press L2, L1, L2, L1, Up, R1, R2, R1, R2, Down, Select. If you entered the code correctly, the screen will fade out and return. Press Start and new options will be unlocked at the main menu.
Game Shark Codes
Master Code (Must Be On) 0E3C7DF2 1853E59EEEACC586 BCD867F2
100 Bells FEA9EB9E BCA99BE7
200 Doops Herded FEA9F5FE BCA99B4B
0 Doops Left FEA9F5FA BCA99B83
0 Doops Killed FEA9F586 BCA99B83
200 Gromps Herded FEA9F582 BCA99B4B
0 Gromps Left FEA9F58E BCA99B83
200 Bleeps Herded FEA9F596 BCA99B4B
0 Bleeps Left FEA9F592 BCA99B83
0 Bleeps Killed FEA9F59E BCA99B83
Easy Cowbells 0EA9EB9E BCA99B84CEA9EB9E BCA99BE6
Have Climbing Feather FEA9DC02 BCA99B84
Have Boots FEA9DC06 BCA99B84
Have Swimming Costume FEA9DC0E BCA99B84
Have Power Gloves FEA9DC0A BCA99B84
Have All Herder Items FEA9DC73 BCA99B88DEA9DC72 BDAB9E87FEA9DC7A BCA99B88