So I can have 1 joystick, 2 buttons, 1 start button, and a 1player button? Ug...
I wasn't including the start buttons or coin buttons, just the action buttons and the joystick in the limits. You should not worry about pressing starter start, coin, button 1, and the joystick at the same time.
But the usual maxium limit for a keyboard hack is 1 joystick, 2 action buttons, and (almost) any number of UI buttons (start, coin, pause, escape, tab, etc)
. The reason the number of UI bottons aren't as limited is because you don't need to press them at the same time, like you do need with the joystick and action buttons. A third action button can be added if it is not used at the same time as the other buttons.
Of course, it does depend on the keyboard encoder of the keyboard you are hacking. A high quality encoder could handle 1 joystick and 4 buttons pressed at the same time if hacked correctly. So these encoders might be okay for a 1 joystick, 6 action button hack, if you don't need to press more than four buttons and the joystick at a diagonal.
This is what people have been trying to say about the problems with keyboard hacking.