Radiant Dawn Unlockable Cheats

Unlockables
Game Completion Extras
These are unlocked upon the completion of the game..
Battle Records - Beat the game
Bonus EXP Display - Beat the game
Event Recap - Beat the game
Hard Mode - Beat Easy or Normal Mode
Maniac Mode (JP only) - Beat Hard Mode
New Opening Movies - Beat the game
Sound Room - Beat the game
Theater - Beat the game
Toggle Battle Animations - Beat the game

Screenshots

Unlockable Characters
Aran - Part 1, Chapter 3: Speak to him with Laura.
Calill - Part 2, Final: View the info conversation before 2-F.
Devdan - Part 2, Chapter 3: View the info conversation before 2-3.
Fiona - Part 1, Chapter 7: Joins automatically if she survived 1-6.
Gareth - Part 4, Final: Joins automatically if he survived part 3 of the final chapter.
Haar - Part 2, Prologue: Speak to him with Marcia.
Heather - Part 2, Chapter 1: Speak to her with Brom or Nephenee.
Janaff - Part 3, Chapter 8: Speak to him with Ike or Reyson.
Lehran - Part 4, Final: Joins automatically after viewing Ike's memory scene (second playthrough or higher)
Meg - Part 1, Chapter 4: View the info conversation before 1-4.
Muarim - Part 1, Chapter 7: Joins automatically when Tormod is recruited.
Nasir - Part 4, Final: Joins automatically if he survived part 3 of the final chapter.
Oliver - Part 4, Chapter 4: Speak to him with Rafiel.
Pelleas - Part 4, Chapter 2: Joins automatically if he survived 3-13 (second playthrough or higher)
Renning - Part 4, Final: View the info conversation before 4-F.
Stefan - Part 4, Chapter 3: Move Micaiah, Lethe or Mordecai onto the tile 11 up and 1 accross from the bottom right tile.
Tormod - Part 1, Chapter 7: Speak to him with Sothe.
Ulki - Part 3, Chapter 8: Speak to him with Ike or Reyson.
Vika - Part 1, Chapter 7: Joins automatically when Tormod is recruited.
Volke - Part 4, Chapter 5: Pay him 3000G with Bastian or Elincia.
Volug - Part 1, Chapter 5: View the info conversation before 1-5.

source: gamefaqs