At the main menu, select "Options", "Cheats", "Enter New Cheat", then enter one of the following codes to unlock the corresponding cheat option. If you entered the code correctly, a message will appear.

Most Characters - Press Blue, Yellow, Green, Yellow, Red, Green, Red, Yellow.
All Hammer Ons/Pull Offs - Press Red, Green, Blue, Green, Blue, Green, Red, Green.
Auto Kick - Press Yellow, Green, Yellow, Blue(2), Red, Blue, Red. Alternately, successfully complete the "Duran Duran - Rio" Gold Bonus Challenge in Career mode to unlock the "Auto Kick" option.
All Slider Gems - Press Yellow, Green, Yellow(3), Red, Blue, Red. Alternately, successfully complete the "Styx - Mr. Roboto" Platinum Bonus Challenge in Career mode to unlock the "All Slider Gems" option.
Focus Mode - Press Yellow(2), Green(2), Red(2), Blue(2).
Performance Mode - Press Yellow(2), Blue, Green, Blue, Red(3).
HUD Free Mode - Press Green, Red, Green, Red, Yellow, Blue, Green, Red. Alternately, successfully complete the "Alphabeat - Fascination" Platinum Bonus Challenge in Career mode to unlock the "HUD Free Mode" option.
Electrika Steel - Press Blue(2), Red, Yellow, Red, Yellow, Blue(2).
Air Instruments - Press Blue, Yellow, Blue, Red(2), Yellow, Green, Yellow. Alternately, successfully complete the "Aly & AJ - Like Whoa" Platinum Bonus Challenge in Career mode to unlock the "Air Instruments" option.
Invisible Characters - Press Green, Red, Yellow, Green, Yellow, Blue, Yellow, Green. Alternately, successfully complete the "Filter - Take A Picture" Platinum Bonus Challenge in Career mode to unlock the "Invisible Characters" option.

Bonus characters - Successfully complete the indicated task in Career mode to unlock the corresponding character:

Adam Levine: Successfully complete the Maroon 5 "She Will Be Loved" gig.
Adrian Young: Successfully complete the No Doubt "Don't Speak" gig.
Frankenrocker: Successfully complete the "Fall Out Boy - Sugar, We're Goin' Down" Diamond Bonus Challenge.
Gwen Stefani: Successfully complete the No Doubt "Just A Girl" gig.
Shadow Character: Successfully complete the "David Bowie - Let's Dance" Gold Bonus Challenge.
Skeleton Character: Successfully complete the "Poison - Every Rose Has Its Thorn" Platinum Bonus Challenge.
Taylor Swift: Successfully complete the Taylor Swift "Love Story" gig.
Tom Dumont: Successfully complete the No Doubt "Just A Girl" gig.
Tony Kanal: Successfully complete the No Doubt "Don't Speak" gig.

Easy "Secret Notes" and "Treasure Hunt" achievements - Create a setlist containing all "Secret Notes" songs. Then, play Vocals only, set the difficulty to Beginner, and put the microphone in front of a fan. You should get 100% on all songs and get the "Treasure Hunt" and all "Secret Notes" achievements.

Accomplish the indicated achievement to get the corresponding number of Gamerscore points:

Welcome to Band Hero (5 points): Complete the Tutorials.
Rise to Fame (10 points): Complete 25% of the gigs in Career.
Nation's Star (20 points): Complete 50% of the gigs in Career.
World Known (30 points): Complete 75% of the gigs in Career.
Glimmer (10 points): Earn 111 Stars in Career.
Sparkle (20 points): Earn 333 Stars in Career.
Shine (30 points): Earn 555 Stars in Career.
Platinum Blonde (10 points): Earn Platinum level on a Career Challenge.
Iced Out (10 points): Earn Diamond level on a Career Challenge.
Road Most Traveled (20 points): Unlock every venue.
The Long Road Ahead (30 points): Complete Career on any difficulty with any instrument.
M.C. (5 points): Host an online Career game and play a song.
Face to Face (15 points): Complete 25 online Pro Face-Off matches, win or lose.
Till Death Do Us Part (5 points): Play an online Do or Die game.
Nice to Meet You (20 points): Complete the gigs and unlock all of the celebrity characters.
A New Challenge Awaits (30 points): Complete 50 of the Career Challenges at Platinum or Diamond.
Testing the Waters (20 points): Play through every Band Hero song once.
15 Minutes of Fame (5 points): Complete a song as an Avatar rocker.
In the Moment (5 points): Successfully complete a Band Moment.
Star Light, Star Bright (10 points): Score over 10,000 points while in a single Star Power deployment.
A Cool Mill (10 points): Score over 1,000,000 points as a band in any single song in Career or Quickplay.
Fevered Pitch (15 points): 100% a song as a vocalist.
Jack of All Trades (15 points): Complete at least one challenge for every instrument at Gold level or better.
There's no 'I' in 'Band Hero' (15 points): Complete a song with 4 players without any members failing on expert in Career or Quickplay.
Four of a Kind (10 points): Complete a song as 4 of the same instrument on any difficulty in Quickplay or Career.
Star Powered (10 points): Earn an 11x multiplier.
Picture Perfect (15 points): Streak through an entire song without missing a note on medium or harder difficulty.
Treasure Hunt (490 points): Collect all of the Secret Notes.
My First Gig (5 points): Complete a Career gig on any difficulty.
Secret Notes 1 (5 points): "Beautiful Soul" by Jesse McCartney.
Secret Notes 2 (5 points): "Black Cat" by Janet Jackson.
Secret Notes 3 (5 points): "Honky Tonk Women" by The Rolling Stones.
Secret Notes 4 (5 points): "Take What You Take" by Lily Allen.
Secret Notes 5 (5 points): "Like Whoa" by Aly & AJ.
Secret Notes 6 (5 points): "She Will Be Loved" by Maroon 5.
Secret Notes 7 (5 points): "Let's Dance" by David Bowie.
Secret Notes 8 (5 points): "Bring Me to Life" by Evanescence.
Secret Notes 9 (5 points): "Lips of an Angel" by Hinder.
Secret Notes 10 (5 points): "Love is a Battlefield" by Pat Benatar.
Secret Notes 11 (5 points): "Don't Speak" by No Doubt.
Secret Notes 12 (5 points): "I Heard It Through the Grapevine" by Marvin Gaye.
Secret Notes 13 (5 points): "Wannabe" by Spice Girls.
Secret Notes 14 (5 points): "Y.M.C.A." by Village People.
Secret Notes 15 (5 points): "So Yesterday" by Hilary Duff.
Secret Notes 16 (5 points): "Ocean Avenue" by Yellowcard.
Secret Notes 17 (5 points): "Dirty Little Secret" by The All-American Rejects.
Secret Notes 18 (5 points): "Oh, Pretty Woman" by Roy Orbison.
Secret Notes 19 (5 points): "Kung Fu Fighting" by Carl Douglas.
Studio Time (10 points): Create a GH Studio song.