Paradise Found is developed for Windows, but you should still be able to play the game on any OS by running the jar file, 
providing you have Java installed on your system with all the resources needed. 
However, JavaFX (needed for videos) is often not included in the typical Java installation. 

To make the game run properly, you must make sure that the JDK/JRE (java installation) 
used when launching the game has JavaFx included. One such JDK is Liberica JDK which 
is the one used by the game and which can be downloaded here: 
https://bell-sw.com/pages/downloads/

The game uses JDK 12 but any Liberica JDK/JRE later than that should also work.

IMPORTANT: Make sure that you download the package that includes JavaFX/OpenJFX/LibericaFX (names can differ). If you are unsure, download the largest package (usually named Full JDK/JRE).

Then, after/during installation, you must also make sure this JDK/JRE becomes the default for your system. If you didn't already have Java installed, it should be automatically.