Games That Weren’t 64 has released the attempt/proof of concept of the game god-sim Populous by Peter Molyneux.
Coder, Frank Hugenroth, got in touch with GTW64 in 2015 and confirmed that it was created more as a technical demo for the C64 and was contributed initially as a contribution to an animation/GFX competition.
Andreas Vargas commented on GTW 64 that he made a PRG build based on the source code (link also below).
Link: GTW 64
Link: Download Andreas’ build