If you go to the bottom right corner of the screen you will see a healing jar. Go to the left platform next to the healing jar and remain idle on it. After a few moments a message will appear on tne screen stating you have found the Master Crest.

Complete the game on the indicated setting to unlock the corresponding game mode difficulty.

Unlock Hard Mode:
Complete the game on the Normal difficulty setting to unlock the Hard difficulty setting.

Unlock Maniac Mode:
Complete the game on the Hard difficulty setting to unlock the Maniac difficulty setting.

It is possible to unlock more characters in the game by completing certain tasks during gameplay. Below is a list of the characters and the corresponding task.

Unlock Haar:
Prologue - Part 2, talk to him with Marcia.

Unlock Heather:
Chapter 1 - Part 2, talk to her with Brom or Nephenee.

Unlock Pelleas:
Chapter 2 - Part 4, joins automatically if he survived 3-13 (second playthrough or higher)

Unlock Devdan:
Chapter 3 - Part 2, view the info conversation before 2-3.

Unlock Aran:
Chapter 3 - Part 1, talk to him with Laura.

Unlock Stefan:
Chapter 3 - Part 4, move Micaiah, Lethe or Mordecai onto the tile 11 up and 1 across from the bottom right tile.

Unlock Oliver:
Chapter 4 - Part 4, talk to him with Rafiel.

Unlock Meg:
Chapter 4 - Part 1, view the info conversation before 1-4.

Unlock Volke:
Chapter 5 - Part 4, pay him 3000G with Bastian or Elincia.

Unlock Volug:
Chapter 5 - Part 1, view the info conversation before 1-5.

Unlock Tormod:
Chapter 7 - Part 1, talk to him with Sothe. Unlock Fiona:
Chapter 7 - Part 1, joins automatically if she survived 1-6.

Unlock Muarim:
Chapter 7 - Part 1, joins automatically when Tormod is recruited.

Unlock Vika:
Chapter 7 - Part 1, joins automatically when Tormod is recruited.

Unlock Ulki:
Chapter 8 - Part 3, talk to him with Ike or Reyson.

Unlock Janaff:
Chapter 8 - Part 3, talk to him with Ike or Reyson.

Unlock Calill:
Final - Part 2, view the info conversation before 2-F.

Unlock Renning:
Final - Part 4, view the info conversation before 4-F.

Unlock Nasir:
Final - Part 4, joins automatically if he survived part 3 of the final chapter.

Unlock Gareth:
Final - Part 4, joins automatically if he survived part 3 of the final chapter.

Unlock Lehran:
Final - Part 4, joins automatically after viewing Ike's memory scene (second playthrough or higher).

When you have completed the game the following features become available as options.

Unlock Theatre:
Beat the game

Unlock Sound Room:
Beat the game

Unlock Battle Records:
Beat the game

Unlock Event Recap:
Beat the game

Unlock Bonus EXP Display:
Beat the game

Unlock New Opening Movies:
Beat the game

Unlock Toggle Battle Animations:
Beat the game