In short, if you want the game to work with the itch app, the steps you should follow are:
1st Install "Changelog.txt" in the app (Not the game), this will create an installation folder.
2º Once "Changelog.txt" is installed, locate it in the game library, right click on the game image and select open folder in explorer.
3º Download the game from any browser (the app will always fail).
4º move and unzip what was downloaded in the previously opened folder.
5º Itch.io app should be working now