I will add the interactive syntax feature seeing that everyone wants it.

Now about tracking iterations, from a candidate's POV, I'd be worried about how my work was coming across, at a stage when I might not be ready to show it yet. I think it's respectful of people's privacy to let them show only the final code that they want to show, and not track their every move on the test. If someone did it to me, I'd be unhappy.