As a 24 year old currently hobbiest programmer (looking to change that), I was able to follow along and really enjoyed this article. Anything I can learn technical and close to the "bare metal" I get immense satisfaction from. I have however had experience with registers and contiguous memory etc while working on a fat32 usb interface in C with libusb during my undergrad research. I think a lot of this puzzle-like nature lives on in protocols. That said I definitely agree that spare time is a factor for things like this. At least in the professional world considering the speed of development and computers themselves.