Street Fighter Alpha 3 MAX

Unlock Shin Gouki:
Finish arcade mode as Evil Ryu, then go to the character selection screen,
press and hold Select while choosing Akuma (Gouki).

Unlock EX-M.Bison and Final-Vega:
Finish arcade mode, then go to the character selection screen,
press and hold Select while choosing M.Bison or Vega.

Unlock Final-Vega
Finish arcade mode.

Fight against Shin Gouki (Shin-Akuma):
While selecting Final Battle mode, press L + R

Get bonus ISM pluses
Choose a World Tour or Entry Mode character.
After finish any mode, which allows an Entry Mode character to be played.
(using without any continues)

Fight as Chun-Li (wearing Street Fighter II costume):
Go to the character selection screen and highlight Chun-Li and hold Select
while choosing her. Then, choose X-ism.

Expert R. Dramatic Battle mode (CPU has unlimited specials):
Complete 100 Kumite mode and achieve perfect score.
Then, hold L + R + Select while selecting the option for R.
Dramatic Battle mode. Then, select a world tour character.

Unlock unlimited auto-guard Isms.
Complete Expert R. Dramatic Battle mode.

Fight as Chun-Li wearing Street Fighter II costume:
Go to the character selection screen and highlight Chun-Li and hold Select
while choosing her. Then, choose X-ism. You will now be playing as Chun-Li
with her Street Fighter II costume.

Bonus ISM-pluses:
Select a World Tour or Entry Mode character. Finish any mode that allows
an Entry Mode character to be played without using any continues.

Finish World Tour mode, save the game, then register your World Tour
character in Entry mode. Use that character in the other modes to
unlock the following ISM Plus upgrades.

Supreme Alpha Power: Finish Survival Boss mode.
Status Plus: Finish Arcade mode.
Multiple Taunt: Finish Final Battle mode.
Custom Combo Charger: Finish R. Dramatic mode.
Alpha Power: Finish Survival Arcade mode.