I've never done it before, if anyone has done it, please leave a comment on whether it's difficult or easy for me to follow

I'm now convinced that it's a LuaJIT bug rather than a game bug. The freeze is definitively in findName (in my case the call to game:findName("Tileset") in breakable.lua), and it doesn't have any reason to freeze there. A workaround could be, after defining Game:findName(), to add: jit.of...