''On World of Spectrum you're credited for 16 titles under various publishers - even three self-published titles. What was your primary machine? Which one did you like the most and why?''
I think the CPC became the primary mechinemachine, better colour and sound, less restrictive, more of a "proper" computer. Always liked the CPC, especially the disc version. Spectrum always irritated me with its colour attribute clash.
''Did you actually program the other version(s) (Spectrum or c64 - though the latter seems to be a different game?)? If so, was there any cross-development, and what was the primary machine?''
Can't remember a C64 version, unless Mastertronic commissioned it. I can't remember a Spectrum version either, if it was done Ed Hick (ed: [http://www.worldofspectrum.org/infoseekpub.cgi?regexp=^Ed+Hickman$ Ed Hickman]?) would have done it, he sometimes took the code and produced versions of my games for other machines e.g. MSX.
Normally a Spectrum and CPC game shared very much the same code, with a few tweaks for the different graphic capabilities. For example Terra Cognita on the Spectrum and CPC probably share 90% of the same code.