I found a solution to open it, all you gotta do is
1/ Unzip the file with ANYTHING OTHER than MacOs' default unzipper (I would recommend "The Unarchiver", it's free and can open a whole bunch of other archived files).
2/ Right click + open the app, it will show a popup saying the app cannot be opened and should be moved to the trash. Ignore the message and click "cancel".
3/ Do it again but this time it will show a new option saying "open anyway", click that and you're done ! Enjoy.