FWIW there's still a pretty large delta from Lua and JS as far as embedding targets go. We use to run our whole game state in a 800kB fixed block on a 8mb system heap in vanilla Lua(pre-LuaJIT) with good success.

I've done some poking at various embedded JS frameworks like Duktape and it's pretty easy to trip on various memory leaks[1] that make it really hard to recommend it as a viable platform for memory constrained spaces.

[1] http://point.davidglasser.net/2013/06/27/surprising-javascri...