Cheat: No Failure
To make it impossible to fail a song, insert the following code in the in-game cheats menu. Keep in mind that this cheat will not work in Career Mode: Green & Red, Blue, Green & Red, Green & Yellow, Blue, Green & Yellow, Red & Yellow, Orange, Red & Yellow, Green & Yellow, Yellow, Green & Yellow, Green & Red.

Unlockable: Hyperspeed
To unlock Hyperspeed, go to the in-game cheat menu (found under Options) and insert the following cheat on your guitar: Orange, Blue, Orange, Yellow, Orange, Blue, Orange, Yellow.

Unlockable: Boss Characters
To unlock any boss characters as playable character, simply beat them in the game and they will become unlocked.

Unlockable: Air Guitar
To unlock the Air Guitar, insert the following notes in the Options menu: Blue & Yellow, Green & Yellow x2, Red & Blue x2, Red & Yellow x2, Blue & Yellow, Green & Yellow x2, Red & Blue x2, Red & Yellow x2, Green & Yellow x2, Red & Yellow x2.

Unlockable: Through the Fire and Flames
To unlock the track "Through the Fire and Flames", beat the game.

Unlockable: Performance Mode
To unlock Performance Mode, insert the following notes in the Options menu: Red & Yellow, Red & Blue, Red & Orange, Red & Blue, Red & Yellow, Green & Blue, Red & Yellow, Red & Blue.

Unlockable: Precision Mode
To unlock Precision Mode, insert the following notes in the Options menu: Green & Red x3, Red & Yellow x2, Red & Blue x2, Yellow & Blue, Yellow & Orange, Yellow & Orange, Green & Red x3, Red & Yellow x2, Red & Blue x2, Yellow & Blue, Yellow & Orange x2.

Unlockable: All Songs (Quick Play Mode)
To unlock all of the game's songs for Quick Play Mode, insert the following notes in the Options menu: Yellow & Orange, Red & Blue, Red & Orange, Green & Blue, Red & Yellow, Yellow & Orange, Red & Yellow, Red & Blue, Green & Yellow x2, Yellow & Blue x2, Yellow & Orange x2, Yellow & Blue, Yellow, Red, Red & Yellow, Red, Yellow, Orange.

Unlockable: Songs (Normal)
To unlock songs in the normal fashion, simply pass the song successfully. It will thereafter be unlocked.

Unlockable: Guitarists
You can unlock Tom Morello (of Rage Against the Machine), Slash (of Guns N Roses/Velvet Revolver), Lou (the Devil in the game), and a character called MetalHead by beating them in the game and then purchasing them for $10,000 (Lou costs $15,000).

Unlockable: Saint George Guitar
To unlock the Saint George guitar, complete Career Mode on Medium.

Unlockable: Moon Shot Guitar
To unlock the Moon Shot guitar, complete Career Mode on Easy.

Unlockable: Jolly Roger Guitar
To unlock the Jolly Roger Guitar, get five stars on each song during Career Mode on Medium difficulty.

Unlockable: Nemesis 13 Guitar
To unlock the Nemesis 13 Guitar, complete Co-Op Career Mode on any difficulty.

Unlockable: Rojimbo Guitar
To unlock the Rojimbo Guitar, complete Career Mode on Hard difficulty.

Unlockable: Distant Visitor Guitar
To unlock the Distant Visitor Guitar, complete Career Mode on Expert difficulty.

Unlockable: Bat Guitar
To unlock the Bat Guitar, get five stars on each song during Career Mode on Easy difficulty.

Unlockable: Beach Life Bass
To unlock the Beach Life Bass, complete Co-op Mode on hard.

Unlockable: Neversoft Skateboard
To unlock the Neversoft Skateboard, complete Co-Op Mode on expert with five stars.

Unlockable: PendulAxe Bass
To unlock the PendulAxe Bass, complete Co-op Mode on expert.

Unlockable: El Jefe Guitar
To unlock the El Jefe Guitar, complete Career Mode on expert with five stars.

Unlockable: Tiki Guitar
To unlock the Tiki Guitar, complete Career Mode on hard with five stars.

Unlockable: All Items Available
To make every item available at the in-game store, insert the following lengthy cheat at the in-game cheats menu. Keep in mind that because you're strumming using four buttons, no sounds will play. You'll have to check the store when you're done inserting the password to see if it worked: Green/Red/Blue/Orange, Green/Red/Yellow/Blue, Green/Red/Yellow/Orange, Green/Blue/Yellow/Orange, Green/Red/Yellow/Blue, Red/Yellow/Blue/Orange, Green/Red/Yellow/Blue, Green/Yellow/Blue/Orange, Green/Red/Yellow/Blue, Green/Red/Yellow/Orange, Green/Red/Yellow/Orange, Green/Red/Yellow/Blue, Green/Red/Yellow/Orange.

Unlockable: Bret Michaels of Poison
To make the singer on stage appear as Bret Michaels of Poison fame, insert the following code at the in-game cheats menu: Green & Red x3, Green & Blue x4, Red & Blue, Red x3, Red & Blue, Red x3, Red & Blue, Red x3.

Hint: Battle Lou in Easy Mode
To battle with Lou using Easy Mode notes, try the following. When the battle with Lou begins (on Expert Mode), strum without holding any frets down. When you lose, select the Tutorial option at the Game Over menu. Do the Guitar Battle Tutorial and play through it in its entirety. After the "Lesson Complete" message appears on-screen and the next fret board appears, pause the game and exit. This will bring you back to the Lessons menu.

From here, press the red button, which will bring you back to the list of songs. The battle with Lou should be highlighted. Choose the song, and Lou's note chart will be set to Easy Mode now. Your note chart will still be in Expert Mode, but Lou's will be in easy mode.