Rock Band 2

Successfully complete the indicated task to unlock the corresponding clothing at the "My Closet" menu in the Rock Shop:

Ultimate Goth Outfit: Successfully complete the Impossible Drum Challenge.
Ultimate Metal Outfit: Successfully complete the Impossible Vocal Challenge.
Ultimate Punk Outfit: Successfully complete the Impossible Bass Challenge.
Ultimate Rock Outfit: Successfully complete the Impossible Guitar Challenge.

Select "Tour Challenges" in "Tour" mode. Successfully complete the five decade challenges from 1960s through 2000s. After completing the ten songs from the challenges, you will unlock all other songs.

Enable the "Select Venue Screen" code. Go to the "New Venues Only" option at the "Modify Game" menu. Start the game in Quickplay mode, and choose a song. A "Video Shoot" option will sometimes appears at the top of the "Select Venue" menu. Press Up to display it. The options will be "Indie Genius Video Shoot", "High-Budget Video Shoot", or "Film Student Video Shoot". Select one of them to play with the corresponding alternate background.

Successfully complete the indicated task to unlock the corresponding instrument at the "My Closet" menu in the Rock Shop:

Bomb bass: Successfully complete the Impossible Bass Challenge.
Bone microphone: Successfully complete the Impossible Marathon 2 Challenge on the microphone.
Clear Fender American Deluxe Stratocaster HSS: Join the Rolling Stone Rock Immortals list.
Clear microphone: Successfully complete the Rock Immortal Setlist in World Tour mode on the microphone.
Glowing drum set: Join the Rolling Stone Rock Immortals list.
Goat head guitar: Successfully complete the Impossible Marathon 2 Challenge on guitar.
Gold bass: Successfully complete the Impossible Bass Challenge.
Gold drum set: Successfully complete the Impossible Drum Challenge.
Gold Fender American Deluxe Stratocaster HSS: Successfully complete the Impossible Guitar Challenge.
Gold microphone: Successfully complete the Impossible Vocal Challenge.
Silver bass: Successfully complete the Final Band Challenge on bass.
Silver drum set: Successfully complete the Final Band Challenge on drums.
Silver Fender American Deluxe Stratocaster HSS: Successfully complete the Final Band Challenge on guitar.
Silver microphone: Successfully complete the Final Band Challenge on the microphone. Bonus instruments
Successfully complete the indicated task to unlock the corresponding instrument at the "My Closet" menu in the Rock Shop:

Bomb bass: Successfully complete the Impossible Bass Challenge.
Bone microphone: Successfully complete the Impossible Marathon 2 Challenge on the microphone.
Clear Fender American Deluxe Stratocaster HSS: Join the Rolling Stone Rock Immortals list.
Clear microphone: Successfully complete the Rock Immortal Setlist in World Tour mode on the microphone.
Glowing drum set: Join the Rolling Stone Rock Immortals list.
Goat head guitar: Successfully complete the Impossible Marathon 2 Challenge on guitar.
Gold bass: Successfully complete the Impossible Bass Challenge.
Gold drum set: Successfully complete the Impossible Drum Challenge.
Gold Fender American Deluxe Stratocaster HSS: Successfully complete the Impossible Guitar Challenge.
Gold microphone: Successfully complete the Impossible Vocal Challenge.
Silver bass: Successfully complete the Final Band Challenge on bass.
Silver drum set: Successfully complete the Final Band Challenge on drums.
Silver Fender American Deluxe Stratocaster HSS: Successfully complete the Final Band Challenge on guitar.
Silver microphone: Successfully complete the Final Band Challenge on the microphone.

At the main menu, select the "Extras" option. Choose the "Modify Game" selection, then enter one of the following codes to unlock the corresponding cheat option. Enter the "Extras" menu to toggle a specific cheat on or off. Note: Enabling a code will prevent the game from being saved. Additionally, you cannot use the solo buttons on the neck of the Stratocaster to enter the codes.

Unlock All Songs
Press Red, Yellow, Blue, Red(2), Blue(2), Red, Yellow, Blue to unlock all songs. Alternately, press Triangle, Circle, Square, Triangle(2), Square(2), Triangle, Circle, Square on a controller.

Select Venue Screen
Press Blue, Orange(2), Blue, Yellow, Blue, Orange(2), Blue, Yellow to unlock all venues. Alternately, press Square, L1(2), Square, Circle, Square, L1(2), Square, Circle on a controller.

New Venues
Press Red(4), Yellow(4) to unlock new venues. Alternately, press Triangle(4), Circle(4) on a controller.

Awesome Detection
Press Yellow, Blue, Orange, Yellow, Blue, Orange, Yellow, Blue, Orange. Alternately, press Circle, Square, L1, Circle, Square, L1, Circle, Square, L1 on a controller.

Breakneck Speed
Press Orange, Yellow, Orange, Yellow, Blue, Orange(2), Blue. Alternately, press L1, Triangle, L1, Triangle, Square, L1(2), Square on a controller. This code increases the scroll speed of the instrument tracks.

Performance Mode
Press Blue(2), Red(2), Yellow(2), Blue(2). Alternately, press Square(2), Triangle(2), Circle(2), Square(2) on a controller. Performance mode removes the track display.

Stage Mode
Press Blue, Yellow, Red, Blue, Yellow, Red, Blue, Yellow, Red. Alternately, press Square, Circle, Triangle, Square, Circle, Triangle, Square, Circle, Triangle on a controller. Stage mode tweaks the game for live, public performances. Note: This code also disables failing songs and pausing the game.