Street Fighter Alpha 3 cheats and cheat codes for Dreamcast

Unlock Super Akuma:
Go to the fighter selection menu and highlight Akuma, then 
hold start and hit A. 

Unlock Super Vega:
Choose training, arcade or VS mode. Go to the fighter selection 
menu and highlight Vega, then hold Start and hit A.

Unlock Super Gouki:
Go to the fighter selection menu and highlight Gouki.
After hold Start and hit A. 

Tougher World Tour:
Reach at least 3,000,000 points in WorldTour mode. Defeat in the final 
battle Juli/Juni and Shin Vega. If you win you will get to GOKUENTOU 
island. Beat the toughest opponent.

Play as EX-Vega (Shin-Bison):
Complete the game with a World Tour character that you have entered 
into the game. Then finish arcade mode with a difficulty of 8,
without using a single continue. If you done, you can play as 
EX-Vega in VS, arcade and in training mode. To select him, 
highlight Vega at the fighter selection screen and hold on 
to start and any button.