Wow. Thank you all for this amazing call to action! It’s such a shame that he encountered legal action. Fortunately he did get his demo out there (and hopefully some full copies!), as I got the demo on a cd pack in for (I think) Australian PC User magazine, sometime in 1999. I’m still going through the Internet Archive trying to locate the exact issue.
I had not thought of decompiling the z5, indeed I didn’t know it was possible. Thank you for uploading the output - it will be an interesting read later, hopefully after playing as I’m sure some of the content will give away the ending!
Years ago I did locate his archived Success Information website and attempted to email some people who I thought could be him through LinkedIn but never heard back, or those emails went with or without bounce into some void. Calling is not something that occurred to me - how cool! Good luck and thank you!