Re: but that's the same as everyone elses review!
Someone else has pointed out that you forgot about the screen and the button controller. The former is obviously essential, but as it sounds like the buttons aren't even debounced, you could get the same functionality by just connecting some mini switches up to GPIO.
Oh, and you really don't need a Pi3 for FUSE: A Pi Zero would work just fine, and save you some money for that screen (I'm a bit vague on the Speccy's screen, but Pimoroni's HyperPixel would probably work fine).
There's no question that someone, young or old, could easily throw together something as basic as this for about the same outlay, if they were determined to cut corners and not at all bothered whether it was actually any good. I'm just not sure why anyone would.