Unless I missed it, no one has metioned the extremely fun puzzle editor. (click icon bottom right corner) .I didn't even know it had this feature for the first 8 hours! It is really fun. You can design your own product and what reagents are allowed to solve it. In the design template, I filled every possible hex with a gold atom and connected them all to see if I could solve it. Yes, but it took over an hour. Best feature of the game. The story is cute and not too hard and like another reviewer, this is the first Zachtronics game I finished.