Modes:
GG Generations Mode / Special Options - Beat all 30 Missions in Mission Mode
EX Arcade/M.O.M. Mode - Unlock all EX Characters and Hold L2
M.O.M. Mode - Unlock all Gold Characters and Hold L1
Gold EX Arcade Mode - Unlock all Gold and EX characters / Hold L1+L2 when starting Arcade/M.O.M. Modes

Characters
Justice - Win at least 20 Missions in Mission Mode / Or, complete her Story Mode
Kliff - Win at least 10 Missions in Mission Mode / Or, complete his Story Mode
Gold / Black Characters - Defeat the character's Gold Form in Survival Mode / Play through all paths of his or her Story Mode.