Its a know issue with other pads. They are not in the Amiberry database.
Ones that are, will work fine once set.
If using the pad that comes with GS, you will find all buttons work fine.
In regard to real 9pin CD32 pad, its already been reported. Needs extra code to deal with shift register.
As SkulleateR linked to thread. Joypad remapping is coming.
even if it wasn't Play/Pause/Start is mapped to the A600GS menu so... I couldn't play the game anyway...
I reported this and said exactly same thing, remove keyboard and move menu to select.
As a crude way around it, rapidly tap start, it will trigger start button.