A couple things to note.
From The Lost Media Wiki
1. While unlikely, it could be possible that the game in the Lemon 64 thread might not be from Orpheus, Ocean Software also pitched a port for ZX Spectrum and C64 to Nintendo, but was also denied.
2. Here’s some of the people who worked at Orpheus if you want to get more contact about this; Geoff Phillips (he has an account on c64.com but it seems defunct), Richard Wilkins, John Marshall, and Paul Kaufman (The president of Orpheus).