Extra Characters and Mobile Suits 

Unlockable                        How to Unlock 
Any Mobile Suit for a Pilot       Finish their story mode at least once.
Milliardo Peacecraft and Epyon    Finish Heero's story in Original Mode.
Master Asia and Master Gundam     Finish Domon Kasshu's Original Mode
Musha Gundam                      Beat Original mode 
                                  with all 6 protagonists - Amuro, Kamille,
                                  Judau, Domon, Heero & Loran