I finally managed to catch up… This is good. Very good.
The level of strangeness feels right in a way that’s difficult for me to put into words, but I can say that it doesn’t feel arbitrary. You’ve found a good balance between explaining things and presenting them as they are for the reader to interpret or remember for later.
I think that, from a technical/skill point of view, the recent days are done a bit better than the first ones, but the difference isn’t so large that it would be jarring.
If you’d like your sprite workflow to be more efficient, you could look into Layered Images. That would avoid having to export each possible combination individually. I’m not really clear on how they work, though, or if there are any reasons you might want to avoid using them.