Unity has the ability to import pieces of code written (and compiled) in other languages; they are called Native Plugins, and this tutorial will teach you how to build them.
If there’s a term which is often misunderstood, that’s for sure hacking. When it refers to softwares, it usually gets a negative connotation which smells of piracy and copyright infringements. This post will not cover any of these topics; quite the opposite, I strongly discourage readers from taking any action which will damage (directly or indirectly) other developers. That said: yes, this post will be a practical tutorial to hack into Unity games. You can use the techniques and tools described in this post to check how safe your games are. If you’re a developer, you’ll also find useful snippets of code and technique to add an extra layer of protection to your games.