Regarding your first statement - that’s why I suggested simplistic pixel art! You can just make b/w images with resolution close to 16*16 and they would fit nicely in twine. (Maybe just as progress bar on top)
Regarding multi - yeah it’s not for everyone, but it was worth to try)
Little side note, we are working on twine game Hyper Farm atm (you can guess the premise), and I would really like to know you opinion about it! You can find me on our discord server, linked in Titanum game page (cheeky self promotion, hue hue hue) https://durak1251.itch.io/titanum