Guitar Hero II Unlockable: Face-off Mode
Complete the game on medium or higher

Guitar Hero II Cheats
Unverified. On the main menu, directly depress the colored key without any other input.

Performance Mode ... YELLOW, YELLOW, BLUE, YELLOW, YELLOW, ORANGE, YELLOW, YELLOW
Hyper Speed ... ORANGE, BLUE, ORANGE, YELLOW, ORANGE, BLUE, ORANGE, YELLOW
Air Guitar ... YELLOW, YELLOW, BLUE, ORANGE, YELLOW, BLUE
Eyeball Heads ... BLUE, ORANGE, YELLOW, ORANGE, YELLOW, ORANGE, BLUE
Moneky Heads ... ORANGE, BLUE, YELLOW, YELLOW, ORANGE, BLUE, YELLOW, YELLOW
Flaming head ... ORANGE, YELLOW, ORANGE, ORANGE, YELLOW, ORANGE, YELLOW, YELLOW
Horse head ... BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE
Hyper Speed ... ORANGE, BLUE, ORANGE, YELLOW, ORANGE, BLUE, ORANGE, YELLOW

PAL version Codes
PAL region has different codes from the NTSC version of Guitar Hero 2.

Air guitar ... BLUE, YELLOW, ORANGE, BLUE, YELLOW, YELLOW
Eyeball Heads ... YELLOW, ORANGE, BLUE, ORANGE, BLUE, ORANGE, YELLOW
Hyper Speed ... YELLOW, ORANGE, BLUE, ORANGE, YELLOW, ORANGE, BLUE, ORANGE
Monkey Heads ... YELLOW, YELLOW, BLUE, ORANGE, YELLOW, YELLOW, BLUE, ORANGE
Flaming Head ... YELLOW, YELLOW, ORANGE, YELLOW, ORANGE, ORANGE, YELLOW, ORANGE
No HUD performance mode ... YELLOW, YELLOW, ORANGE, YELLOW, YELLOW, BLUE, YELLOW, YELLOW

Horse Head ... BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE, ORANGE, ORANGE, BLUE, ORANGE

Guitar Hero II Unlockable: Unlock All

To unlock everything in the game, insert the following code on your guitar at the title screen: Blue, Yellow, Orange, Red, Orange, Yellow, Red, Yellow, Red, Yellow, Red, Yellow.

Guitar Hero II Hint - Ripper Guitar Glitch
Unverified. Before you follow the glitch you must choose to do one of the two glitch(es):

(A) Giving a normal guitarist 'The Scythe'. Go to whatever difficulty you would like to play on, choose the Grim Ripper as a guitarist. Go to select guitar and pick the scythe, (seeing as it was the old one, read (B) for more info). Now select the prefered guitarist, and now he is using 'The Scythe'. He only has the scythe because it didn't go to guitar select mode like in co-operative after selecting guitarist.

-- or --

(B) The Grim Ripper with a normal guitar. Go to whatever difficulty you would like to play on, choose any guitarist (except Grim Ripper), then choose your prefered guitar. Now select the Grim Ripper, it should still have your prefered guitar because it didn't go to the guitar select screen and auto-choose scythe like in co-operative mode.

These two glitches only works in career mode.