Enter the following codes (without the quotes) in Adventure mode by pausing the game and pressing Up, Up, Down, Down, Left, Right, Left, Right, B, A to bring up the cheat code entry prompt (some of the codes will disable achievements from being earned and the game from progressing when entered).
Animal Sounds: Enter 'patrickdugan'.
Remove Film Grain: Enter 'reverb'.
Faster Music: Enter 'upthejoltcola'.
Squeaky Voices: Enter 'chipmunks'.
First Person/Headless Mode: Enter 'MorgyTheMole'.
Infinite Secondary Items: Enter 'stevebrooks'.
Push Objects Away from Player: Enter 'SouthPeak'.
Disable Special Tracking Cameras: Enter 'ihatefunkycameras'.
Increase the Size of Jennifer's Chest: Enter 'ArieannDeFazioWithFlair'.