Kingdom Hearts: Birth by Sleep Cheats

Secret Bosses
These Bosses are only available to fight with after you have cleared the Final Story. They are accessible during Terra, Ventus and Aqua's Story.

Lingering Spirit Vanitas: Clear Final Story
Mysterious Figure: Beat Lingering spirit Vanitas at Keyblade Graveyard.

Trinity Archives
To unlock the Trinity Archives on the main menu, you must do the following:

Trinity Archives: Complete the Story with any Character

Secret Movie: Blank Points
To unlock a secret preview to the next major game in the series at the end of the game, you must do the following:

On Critical Mode: Complete the Final Episode
On Proud Mode: Complete the Final Episode
On Standard Mode: Complete the Reports Section 100% and Complete the Final Episode

Final Chapter
Acquire every Xehanort report as each character, then complete all three story modes to unlock the Final Chapter.

Final Chapter: Acquire all Xehanort Reports

Trophies
Complete each requirement to unlock the specified Trophy in Trinity Archives:

Arena Sweeper: Proof you have finished every quest.
Clockwork: Proof you have played for 80 hours or more.
Dairy Devotee: Proof you have activated Frozen Fortune 30 times.
In the Munny: Proof you have amassed 33,333 munny.
Keyslinger: Proof you have taken out 9,999 Unversed.
One Down: Proof you have finished one character's story.
Power Walker: Proof you have taken 99,999 steps.
Trinity Trophy: Proof you have finished all the stories in Proud Mode or above.