When using the instructions listed here http://gamesx.com/wiki/doku.php?id=controls:x686button (http://gamesx.com/wiki/doku.php?id=controls:x686button) for modifying a genesis 6 button controller, I've run into a minor issue. When playing Street Fighter 2 or Super Street Fighter 2 the controller works, but the default button assignments are incorrect. Only the kicks are affected. Normally A = weak, B = medium, C = strong kick. However, when using this mod A = strong, B = weak, C = medium kick. I can change the button assignments in options to get around this, but the controller buttons in the menu show the corresponding ABC XYZ as if they're set correctly. For me to correct the controls I have to set ABC to CAB.
Oddly enough though, the controls seem correct in the Fatal Fury games. Did the original Capcom adapters packaged with Street Fighter 2 behave the same way or did they have some extra circuitry that set up the buttons correctly by default?