Fun last second idea, i really like the addition of the actual formulas. I'd have liked something else than clicking though which emphasizes the spinning nature more. Minor annoyance that the menus stay stuck when opening them instead of closing once you open another menu. Also would benefit some kind of notification popup once an upgrade becomes available.
Your previous game idea also sounds like a lot of fun if you ever get around to it, reminds me of something like Spore.