The only real suggestion I have is to grab the contents of the https-requirements folder again and reinstall them onto your machine. I just performed a fresh install of this project and the node server started just fine.
if the node server is starting, then my next suggestion would be to check the URL you're opening. From the Readme, you need to go to https://localhost/example.html, not just https://localhost. you'll likely be prompted with a security warning from your browser due to the self signed cert, but once you navigate past that warning you should see the example page for the embeddable framework.