Air Guitar and Super Rocker
Go to the mode selection screen to enter the button combinations on the guitar controller for activating the listed cheat. Take the axe away from your character, forcing him to play air guitar, by entering "Orange," "Orange," "Blue," "Yellow," "Orange." Keep your character's rock meter green so that you do not fail a song by inputting "Yellow," "Blue," "Orange," "Orange," "Blue," "Blue," "Yellow," "Orange."
Faces in the Crowd
On that same mode selection screen, enter the following sequences to change the look of the characters in the crowd. Give fans monkey heads with the code: "Blue," "Orange," "Yellow," "Yellow," "Yellow," "Blue," "Orange." Give the fans skull heads by entering "Orange," "Yellow," "Blue," "Blue," "Orange," "Yellow," "Blue," "Blue."
Secret Character Glitch
Normally, you can't play with one of the two secret characters (Grim Reaper or Izzy Sparks) on a given difficulty level until you finish that level. This trick allows you to do just that. First, unlock one of the secret characters by finishing any difficulty level and select one of the two characters. Now go to a new difficulty level and do not move your cursor on the character selection screen. Press the "Green" button to enter as Axel Steel. When you start a song, you'll see that whichever secret character you had selected on the previous difficulty level is your rocker instead of Axel. If you switch characters while playing on this difficulty level, the effect will be lost.
Shop for Characters
Grim Reaper and Izzy Sparks can also be accessed the hard way -- by purchasing them. You will earn money for each successful song you complete above the "Easy" difficulty level. Head into the game's shop to buy Izzy for $5,000 and Grim Reaper for $8,000.