The full game is on Itch.io
With the full game do you mean the patch 0.39 even if it says it's still in beta? If I buy the game now that means that I still have access to the future updates (3 versions behind the current beta build). Or am I missing something?
Once you own the game you will get all updates up to the final version
Upload a GOG version (They have Adult games now)
https://www.gog.com/en/games?query=vr
