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

... B, O, O, B, O, O, B, O, O, B, O, O, B, O, O, B, O - Horse Head

Submitted by l0n3ly_w17h0u7_h3r
Addition by Bobby Bird (teko101)