You may run into the following issue when installing the Project Paradise Demo on Windows (tested on Windows 10). If you're having a different problem with your demo copy on Windows, please post here.
ISSUE: When attempting to run the installer, the following message appears. This is because our application and new and not recognized by Microsoft's database of popular software.
NOTE: Always be careful running software from unknown sources on your computer!

SOLUTION: First, click "More info". Next, click "Run anyway". And that's it!