Shiva - Streets of Rage Real Boss

We all know Shiva is the boss in the end of SOR3... ok jokes aside the Boss is Galsia with his knife...
Made this cause DLC was out and I finally playing with Shiva... When I was young I unlocked Shiva by beating him in Streets of Rage 3 but had no idea how... only after years discovered you had to do some buttom press after beating him, but today we can play him in a easier way in streets of rage 4 :D