I've been going through this with my kids and some kids from the neighborhood. They really dig it, especially the first part but then the steps become too large to comprehend and the 'show components' bit stops working.<p>Some seem to check out around the half adder / full adder step, some don't understand why it could matter to create an optimal design and some are like fish in the water. I do my best to guide them through the levels without giving too much away but it is clear that even though the concept is great without close guidance pretty much all of the people that I've introduced to it would quit well before reaching the end.<p>I would love to see some stats on what a funnel like view from the first to the last entries looks like. I suspect that very few of the entrants make it to the last stage.