I don't understand what you mean by that. It shouldn't require any installation besides placing the file next to the exe and pck file. Do keep in mind it has to retain its name. It must be named exactly "donation_key" for the game to register it.
Oh! My apologies, I wasn't even aware there was an itch app. I will check it out tomorrow and see how the process works through there, and update the installation guide as needed, though for now the web version should work perfectly. ^^
