The following are some known issues running the Project Paradise Demo version on Mac OS Big Sur (Version 11). If you're having a different problem with your demo copy on Big Sur, please post here.
ISSUE: When attempting to start progam, a system error is triggered: “You do not have permission to open the application”. This is a common issue with many programs attempting to run on Big Sur. You can read more on Apple's official support page here.
SOLUTION 1: First, confirm that permission settings for the game are correct. To do this, right click on the game program and select “Get Info”. At the bottom of this window, make sure that next to your user name you have the “Privilege” option set to “Read & Write”. Then, try right clicking the application and then selecting "Open".