Wii Remote Usage
If you want to play this game with a friend on your Wii and don't have a spare guitar, you can play the game using the Wii Remote. Here's how the buttons correspond:

B Button	Green
Right (D-Pad)	Red
A Button	Yellow
1 Button	Blue
2 Button	Orange

PendulAxe Bass
How to unlock: complete Co-op Mode on expert.

Saint George Guitar
How to unlock: complete Career Mode on Medium.

Hyperspeed
Description: Unlock Hyperspeed,
How to unlock: 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

Nemesis 13 Guitar
How to unlock: complete Co-Op Career Mode on any difficulty.

Jolly Roger Guitar
How to unlock: get five stars on each song during Career Mode on Medium difficulty.

El Jefe Guitar
How to unlock: complete Career Mode on expert with five stars.

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.

Precision Mode
How to unlock: 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.
Bat Guitar
How to unlock: get five stars on each song during Career Mode on Easy difficulty.

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.

Precision Mode
Description: unlock Precision Mode
How to unlock: 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

Distant Visitor Guitar
How to unlock: complete Career Mode on Expert difficulty.

Boss Characters
Description: Unlock any boss characters as playable character
How to unlock: Just beat them in the game and they will become unlocked.

Songs
The following songs can be unlocked in the game:

An Endless Sporadic	"Impulse"
Backyard Babies	"Minus Celsius"
Bret Michaels Band	"Go That Far"
Die Toten Hosen	"Hier Kommit Alex"
Dragonforce	"Through the Fire and the Flames"
Fall of Troy	"FCP Remix"
Gallows	"In the Belly of a Shark"
The Hellacopters	"I'm in the Band"
Heroes del Silencio	"Avalancha"
In Flames	"Take This Life"
Kaiser Chiefs	"Ruby"
Killswitch Engage	"My Curse"
LA Slum Lords	"Down N Dirty"
Lacuna Coil	"Closer"
Lions	"Metal Heavy Lady"
NAAST	"Mauvis Garcon"
Prototype	"The Way It Ends"
Revolverhead	"Generation Rock"
Rise Against	"Prayer of the Refugee"
Scouts of St. Sebastian	"In Love"
Senses Fail	"Can't Be Saved"
The Sleeping	"Don't Hold Back"
The Stone Roses	"She Bangs the Drums"
Superbus	"Radio Song"

Tiki Guitar
How to unlock: complete Career Mode on hard with five stars.

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.

Beach Life Bass
How to unlock: complete Co-op Mode on hard.

Rojimbo Guitar
How to unlock: complete Career Mode on Hard difficulty.

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

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).

Neversoft Skateboard
How to unlock: complete Co-Op Mode on expert with five stars.

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.

Air Guitar
Description: Unlock the Air Guitar
How to unlock: 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

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.

All Songs (Quick Play Mode)
Description: Unlock all of the game's songs for Quick Play Mode
How to unlock: 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

Songs (Normal)
Description: Unlock songs in the normal fashion
How to unlock: Simply pass the song successfully. It will thereafter be unlocked.

How to unlock: complete Career Mode on Easy.

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.