I had more fun with this than I expected to. The only problem is that I got to the Full Adder level, then clicked on "About" and when I went back, my progress was not saved. It would be nice to have a way of saving and a way of showing how I built each component.
Yes that is annoying. Also all progress is lost if you leave the page. I am considering saving the state in local storage so you can return to the page and continue where you left of. Also a great suggestion to save previous levels so you can go back and review them.
