Oh that's odd, but never checked that part out lol. Yeah 9 and 0 yet another odd Spectrum keyboard selection :) Should work with Kempston as well if your emulator is setup for it.
Yeah, had similar issues myself with stuff I have downloaded, even stuff I paid for.
https://dvader.itch.io/rollerball
Should take you to the main download page.
Thanks again for the kind comments, let me know if you manage to complete it!