It was released 24hr before the Steam/GOG/Itch release on RARBG.

Interesting, but this means it was actually you that "copied" my game, because this is a sequel of my flash game from 2014 :) Cheers!

Standard Unity URP shaders, post-processing and lightning. I just tweaked a lot until it clicked. Cheers.

Yes, Unity. It's not made from any sample project for sure ;) Cheers!