We Make Games at Tomorrow Corp – Our Custom Tools Tech Demo

I'm mostly curious about:

- How is it possible to move back and forth in the game as shown around 08:00? I don't know if the game compiled to native code directly but I think it's easier if it's running inside a VM (and I do see "vm" in the video)

- How does one make these kind of tools in general? I feel these are super helpful for any game developer out there.