"...With 16, 48 or 64k to play with, it was pretty easy for one person to fill all the memory in a few weeks' work..."
Or 32k in the case of my own erstwhile BBC B+
I think as well, it's worth remembering that because of the severe limitations of the hardware back in the say, the games had to be very playable, as well as generally being quite unique, in order to allow gamers to look past those sometimes obvious limitations.
Elite (the original on the BBC) was a masterclass in what could be squeezed out of them. When the original sourcecode was released, it turned out that there were no unused spaces (made the code verrry difficult to read) - every line was full to the brim because it was literally the only way to fit it all in!