The thing I loved about Spectrum was game loading graphics from tape. Spectrum had a very strange video memory layout, so the bitmap would load first into different thirds of the screen (but still all monochrome). And then at the end the attributes (which were much smaller due to the 8x8 size) would load almost instantly, "painting" the monochrome image in a final splash! So this is very nostalgic for sure.
And the funny thing is, I like the spectrum renders better than the "perfect" ones from a modern computer :-)
I also remember that there existed cool loaders that were able to paint the image in arbitrary order. It was pretty impressive because it required doing calculations in the tight loop which calculated the delay between slopes of the signal which came from tape.
Below is a link to one I did. It loads in various patters, including writing, and from what I remember was spread out over the time it took to load the game so there was always something going on.
It wasn't the best game around, hopefully the loader made up for that!!
I remember a loader where you could play a game of Mastermind while the game was loading. Magic. Blew my mind, it's the kind of thing that wasn't supposed to be possible, yet it was...
There is something like a 171 clock cycle delay in the regular tape loaded routine between looking for edge transitions in the audio signal. You just break your program up into pieces that fits into that. I did one that did a countdown timer and broke it into exactly the loop delay but I suspect the tape loading would be tolerant to a little more inexactness.
And the funny thing is, I like the spectrum renders better than the "perfect" ones from a modern computer :-)