I used to like Lua a lot...

https://garry.tv/2014/08/16/i-fell-out-of-love-with-lua/
I used to like Lua a lot and now I don’t. I think anyone intending to add a scripting language to their game/engine should seriously consider using Javascript instead.

Javascript is used all over the web. It’s only going to end up getting used more and more. Google, Mozilla and Microsoft are all working to make it faster and faster.

Ultimately if we have to teach people a scripting language, lets teach them a language that will serve them in the future. Sure the jump from Lua to Javascript isn’t that great, but if you skip Lua there’s no need to make a jump at all.

The only problem with Lua is that is uses too many curly braces. The old languages like Fortran, Cobol, Algol, PL/I, Basic, Pascal, APL, and some relatively newer languages like Ada and Smalltalk do not use a single curly brace for anything. Pascal can use them for comments, but that's about it.

The more curly braces a language uses, the more design flaws and inconsistencies it has. That's an undeniable fact. Lua, Ruby, and Python are better designed than Perl, PHP, and JavaScript. Pascal, Ada, and Eiffel are better designed than C, C++, and Java. I can't explain why that is, but it's true.