For a wiring diagram of an Y-cable with which you can use two joysticks on your Amstrad/Schneider CPC, see [[Joystick Y-cables]].
Also most Most of the games didn't make use of the Fire1 button, and even more less of the undocumented Fire3 button.
As Amstrad CPC do sport only one Joystick connection, it is possible to customise some kind of 6 button Joystock quite easily, using the 4 directions of the second button as additionnal fire, for use in 1 player games.