Arrgh!  I left the Genesis off the list right after I mentioned it above!
So the amended Ys platform list is:

 

1. PC-Engine/Turbo

2. Super Famicom/Super NES

3. Sega Mark III/Master System

4. Sega Mega Drive/Genesis

5. Sega Saturn

6. Sony PlayStation 2

7. Sony PSP

8. Apple II GS

9. PC-8801

10. PC (DOS)

11. PC (Windows)

 

Eleven platforms is even more impressive ...

 

Daniel Ladner