This game needs a bit more polish.
When the MC confronts his not-mother in the classroom in Chapter 1 and immediately chokes her, he gets kicked in the nuts.
Later, she'll say:
There's other dialogue like this that doesn't fit the context of previous choices or events.
Also, I don't think the 1px outline is enough. I suggest changing it to 2 or even 3px, and adding a configurable textbox.
Also also, there's a typo in this variable name: define gui.charaters_text_outlines = [ (1, "#00000080", 1, 2) ]
Edit:
Chapters 1 and 2 seem to indicate that the MC is much younger than a university student. For instance, the doorknob being at the MC's eye level, her considering him to be a kid/child, or thinking "he's starting to be at the age he's interested in girls"... Even if he's (only) 18, he would've been interested in girls for a few years.