Bonus photos
At the "Press Start" screen, quickly press Blue, Yellow, Orange(3), Blue(3), Yellow, Orange to unlock bonus photos. If you entered the code correctly, a message will appear.

"The End" song
Successfully complete Story mode to unlock "The End" song from Abbey Road.

Challenges
Successfully complete the indicated chapter in Story mode to unlock the corresponding challenge:

The Cavern '63: Chapter 1
The Ed Sullivan Show '64: Chapter 2
Shea Stadium '65: Chapter 3
Budokan '66: Chapter 4
Abbey Road '66-'67: Chapter 5
Abbey Road '67-'68: Chapter 6
Abbey Road '68-'69: Chapter 7
Apple Corps Rooftop: Chapter 8

Photos
Successfully complete the following tasks to unlock all 108 photos:

Get three stars on each song in Story mode to unlock a photo.
Get five stars on each song in Story mode to unlock a photo.
Successfully complete a chapter in Story mode with at least three stars on all songs to unlock a photo.

Successfully complete the following challenges with the indicated number of total stars to unlock more photos:

The Cavern '63: 20 stars
The Ed Sullivan Show '64: 20 stars
Shea Stadium '65: 25 stars
Budokan '66: 25 stars
Abbey Road '66-'67: 30 stars
Abbey Road '67-'68: 30 stars
Abbey Road '68-'69: 35 stars
Apple Corps Rooftop: 30 stars

Successfully complete Chapter 8 to unlock the final two secret photos.

Movies
Successfully complete the indicated task in Story mode to unlock the corresponding movie:

Intro movie: Begin Story mode.
Chapter 1 movie: Successfully complete Chapter 1.
Chapter 2 movie: Successfully complete Chapter 2.
Chapter 3 movie: Successfully complete Chapter 3.
Chapter 4 movie: Successfully complete Chapter 4.
Chapter 5 movie: Successfully complete Chapter 5.
Chapter 6 movie: Successfully complete Chapter 6.
Chapter 7 movie: Successfully complete Chapter 7.
Chapter 8 movie: Successfully complete Chapter 8.
Outtro movie: Successfully complete Story mode.

Instrument icon plates
Get the indicated number of trophies to unlock the corresponding instrument icon plate:

Silver: Unlock 15 trophies.
Gold: Unlock 30 trophies.
Platinum: Unlock 50 trophies.

Trophies
Successfully complete one of the following tasks to get a trophy:

A Little Help From My Friends (Bronze): Start a Story with a four player band.
All Together Now (Bronze): Get a Guitar, Bass and Drum unison bonus on the songs listed on the Trophies.
In Seconds Flat (Bronze): Maintain Beatlemania for 60 seconds.
Shake It Up, Baby! (Bronze): Use Beatlemania at least 5 times in a single song using either Bass or Guitar.
Eight Days a Week (Bronze): Get an 8x Band Multiplier.
Like a Million Suns (Bronze): Score 1,000,000 points in a single song.
Authenticity (Bronze): Finish any song as a Bassist with Lefty Mode turned on, hitting at least 50% of the notes.
How Could I Dance with Another? (Bronze): Score 100% playing I Saw Her Standing There on Expert Bass.
Day Tripper (Bronze): Start a new Story save file and reach the credits within 24 hours.
Let's Get Some Levels (Bronze): Calibrate your system for the optimal experience.
Elmore James Got Nothing on This (Bronze): Get 85% or better on all solos in The Beatles: Rock Band on Expert Guitar.
Sun, Sun, Sun Here it Comes (Bronze): Get a 350-note streak playing Here Comes The Sun on Guitar
That's It! You've Got It! (Bronze): Get a 350-note streak playing Hey Bulldog on Bass.
Goo Goo G'joob (Bronze): Get a 550-note streak playing I Am The Walrus on Drums.
Do Right By Me (Bronze): Get a 350-note streak playing Ticket To Ride on Guitar.
The Words You Long to Hear (Bronze): Earn a five-star rating for the songs on the Trophies screen as a Vocalist on Hard or Expert.
She Still Sings It with the Band (Bronze): Get all possible Double Fab ratings for every song with 2 vocal parts.
Liverpool Lads (Bronze): Play a song in The Cavern '63 in Story.
Really Big Show (Bronze): Play a song on The Ed Sullivan Show '64 in Story.
Stadium Superstars (Bronze): Play a song in Shea Stadium '65 in Story.
The Final Tour (Bronze): Play a song in Budokan '66 in Story.
In the Studio (Bronze): Play a song in Abbey Road, Studio 2 in Story.
Mr. K Will Challenge the World (Bronze): Finish all 8 Chapter Challenges.
Toppermost of the Peppermost (Bronze): Finish all 8 Chapter Challenges with full star ratings.
I Saw the Photograph (Bronze): Get your first Beatles photo.
The Teachers Who Taught Me WERE Cool (Bronze): Complete all the Beatle Beats.
Doing the Best That You Can! (Bronze): Complete all the Drum Lessons.
Gear Guitarist (Bronze): Earn a Guitar Career Score of 1,000,000.
Ace Bassist (Bronze): Earn a Bass Career score of 1,000,000.
Dazzling Drummer (Bronze): Earn a Drum Career score of 1,000,000.
Sensational Singers (Bronze): Earn a Vocal Harmonies Career score of 1,000,000.
I GOT BLISTERS ON MY FINGERS! (Silver): Score 100% notes hit on Helter Skelter playing Expert Drums.
Better Free Your Mind Instead (Silver): Earn Expert gold stars on the 4 songs listed on the Trophies screen.
No One's Frightened of Playing (Silver): Earn Expert gold stars on the 4 songs listed on the Trophies screen.
And the Band Begins to Play (Silver): Earn Expert gold stars on 4 songs listed on the Trophies screen.
Things That Money Just Can't Buy (Silver): Earn Expert gold stars on the 4 songs listed on the Trophies screen.
Still my Guitar Gently Weeps (Silver): Hit 100% of the notes in either of the solos in While My Guitar Gently Weeps on Expert Guitar.
What I Got I'll Give to You (Silver): Hit 100% of the notes in the solo of Can't Buy Me Love on Hard or Expert Guitar.
We Would Be So Happy, You and Me (Silver): Play Octopus's Garden on Expert Guitar, playing all hammer-ons and pull-offs without strumming.
Won't You Come Out to Play? (Silver): Play Dear Prudence on Expert Guitar, playing all hammer-ons and pull-offs without strumming.
Pick a Moon Dog (Silver): Play Dig a Pony on Expert Guitar, playing all hammer-ons and pull-offs without strumming.
All the Children Sing (Silver): Get all possible Triple Fab ratings for every song with 3 vocal parts.
Passed the Audition (Silver): Play all the songs on Apple Corps Rooftop '69 in Story.
All You Need is Love (Gold): Five-star every song in The Beatles: Rock Band
The Complete Anthology (Platinum): Wow! You've gotten all the Trophies in The Beatles: Rock Band.

Additionally, there are six secret trophies:

Don't Let Me Down (Bronze): You saved a bandmate from failing!
Oh Yeah, All Right! (Silver): Hit 100% of the notes in the solo of The End on Hard or Expert Guitar.
Are You Gonna Be In My Dreams? (Silver): Hit 100% of the notes in the solo of The End on Expert Drums.
In Penny Lane There Is A Barber (Bronze): Get half of the Beatles Photos.
The Love You Make (Bronze): Complete the Encore in Story.
Images of Broken Light (Silver): Get all the Beatles Photos.

Shopping for...