The normal sisze should be at least 12 or 14 I think.
Well, for the initial screen resolution (usually 1920x1080), default font size for Ren'Py goes between 24 and 36, depending of what part of the interface it is. And it's exceptional that a dev change it.
Fonts looks small because the windows, and therefore the font itself, is resized for a smaller resolution.
Notice the two black parts on the side ? They are saying that the window do not match the initial ratio, and they appear because the window's width is smaller than expected. This mean that it's not a 16:9 to 4:3 issue since the width would be higher than expected, and therefore the black parts would then be on top and bottom.
The sad part is that I have my laptop connected to a big TV and still can't read anything.
Well, configure your card/OS correctly then, because I don't see a modern TV, nor a recent game, not being 16:9.
Personally, both far and near sighted (thanks to the age), and astigmatic in top of that, I don't really have problems reading texts in Ren'Py games. At least unless the dev thought smart to lower the size and/or use an exotic font.
