This language looks pretty awesome. Basically, it's a low-level language wrapped in a high-level language (Lua), and it has access to C libraries.
So, you in your code, you have Lua code on the outside, Terra code within special Terra functions, and you can access C within those Terra functions.
It's pretty awesome. It would be great if they also made something like this with Python instead of Lua, with binaries compiled for arm processors (such as for use on Termux or a Raspberry Pi). And, it would be great if they compiled Terra for arm processors, too, and coordinated with Termux, so you could install it with the package manager.