King Of Dragons

Select Same Character
While the first Capcom logo is beginning to fade, quickly hit 
Down, R, Up, L, Y, B, X, and A on Controller One.  The Title 
screen flashes blue, and both players in a two-player game 
are able to play as the same character.

Extra Credits
Play a normal game until you're defeated.  When the 
Continue screen appears, hit Start on Controller Two, then 
quickly hit Start on Controller One.  Choose your character 
with B, your credits will jump up to 99.