Use the amazing Kotlin language with Unity
Uses Puerts, a Javascript runtime built for Unity
Open the hello-kotlin-template Unity project and search for the HelloKotlin scene.
Open the kotlin-unity project with IntelliJ IDEA Community and run the build task to update the code in the Unity project.
Pong Example
For you need to download this, decompress it and copy the dynamic library found in Puerts/Runtime/Plugins/x86_64/puerts.dll to the root of your build folder.