An integration for itch.io

It's a bit of a hack at the moment (hardcoded paths to the itch clients db, useless oauth2 signin), but hey it works. Please use the download via the releases page as the repo itself does not contain any dependencies. Also please note that you have to have the itch launcher installed at the default location!

Also feel free to create an issue if something doesn't work for you :)

• Show games installed through the itch client in Gog Galaxy 2
• Launch games

• Show (not yet installed) purchases in your library
• Install purchased games