Confusing changes to code made by save() - dump()

Everything is saved that you'd expect if you took a 'snapshot' of memory... So:

function foo(a) {
  setTimeout(function() {
    console.log(a);
  }, 1000);
}

foo(42);
save();

will print '42' the next time around, even if it's not global.

The one 'gotcha' is that save() is executed when the interpreter is idle, so:

function foo() {
  console.log("Hello");
  save();
  console.log("World");
}

Will print 'Hello', then 'World', then it will save the state.

It's probably not a nightmare to run Espruino bare-metal on the Pi, but the second you want USB/Ethernet/Video/Sound/etc it's going to turn into an enormous amount of work :)