The code generator is indeed different, the runtime is still Mono. Mono today has two code generators: Mono's built it one, and an LLVM one. Both generate cod

The code generator is indeed different, the runtime is still Mono. Mono today has two code generators: Mono's built it one, and an LLVM one. Both generate code after Mono loads and processes the assembly. Unity developed a different front end to the runtime that does the compilation from IL to C++, the result still requires the Mono runtime to provide services at execution time. They are currently upgrading their Runtime and are making a version with all the greatest features available coming.