Didaktik Gama contain different zx rom (modified), internal chip PIO 8255 using ports 31,63,95,127 and next 80kB ram. For best compatibility with ZX you can replace rom with original zx 48 rom. If you need connect some external devices with kempston joy (and other) please remove chip 8255 from socket and connect pins 14 and 7 in socket (may be via resistor). This cause full software compatibility with zx spectrum 48+ and disable extra ram page and PIO ports.
Your two 9pin joystick ports are home made.