The "Demo" version for free is actually the complete game. The only difference between it and the pay version is the Cheat build of the game offers an in-game cheat menu which allows you to adjust stats at will, which in turn can make some content within the game easier to find.
Viewing post in The Allure of Wanton Cove (Complete) comments
The complete version of the game is available on itch. The old free version was lost when my Patreon account was lost.
The remake of the game is available on Steam. The Steam version has a demo available. https://store.steampowered.com/app/2653920/The_Allure_Of_Wanton_Cove/
Both versions of the game are the same as far as content, but the Steam version is a huge upgrade in terms of art and atmosphere.