Regarding the Mono runtime: To convert the .NET game code (your C# and UnityScript scripts) into JavaScript, we developed a new technology in-house which we ca

Regarding the Mono runtime: To convert the .NET game code (your C# and UnityScript scripts) into JavaScript, we developed a new technology in-house which we call IL2CPP. IL2CPP takes .NET bytecode and converts it to corresponding C++ source files, which we can then compile using any C++ compiler — such as emscripten to get your scripts converted to JavaScript. Expect more information on IL2CPP soon.