To get Akuma you must beat him by fighting him in the "traditional" way (not
with the code.) Set the difficulty to level 5 or higher, choose the original color of your
character, choose the best of 3 round setting, Finish your opponent with a super at least
8 times and don't at least twice. If you did this all correctly, you'll fight Akuma as
your 8th opponent - if you beat him and save your data, he will be selectable by tapping
down at any time in you "?" box. If he beats you and you continue, he will be
gone you'll have to play the last 7 chars over again to get back to him.To get M.Bison,
you must pick your original color and beat the game on level 8 difficulty with someone who
fights Bison as the "Boss" in their Scenario (Like Chun Li, Nash/Charlie, or
Guy).
To keep Dan you must beat the game on level 8 using Dan with his original color.