itch.io

Android

In application settings (tap and hold the app then select detail/settings) scroll down and tap 'clear data', then 'clear all data'

PC

start registry editor (windows + r > type 'regedit' then enter) > find the registry "Computer\HKEY_CURRENT_USER\SOFTWARE\NymphoKyun\SB Orks Ryona BBC" and delete it. Or download and execute once THIS