We were using Luajit with our own extensions with our own binding mechanisms that included automatic translation of indices. And we had A LOT of bindings.

There was some "fun" there. Luajit C functions uses space indentation that becomes tabs every 8 spaces, i.e. mixed tabs and spaces. And his custom assembler for the assembly portions.

I personally spent a lot of time "refactoring code to generate less garbage" as we had purposeful garbage collection in our idle time.

One of the advantages with Lua was that everyone could code in it. I.e. for our games all the artists, sound engineers and producers were developing Lua which was super productive.

But the function signature one in particular - that would have saved me a lot of stress on release nights!