Finaly got how this game works.
Note:
At the opening the main character (the player) explains the girl, Kusuda Maki, is his niece who left her parents home and is now lodging in his house.
I coudn't understand why in the op (apparently some disagreeing) but, throughout the game, it seems to be due to the school she's attending being far from her parents home.
End of Note:
The Talk (2nd. from the top on the right menu) button allows you to pick among 3 independent topics:
1. About the girl (Kusuda Maki) temp job (arubaito)
2. About Maki school life
3. About her parents
Choosing any of those will move only that topic ahead eventually triggering the girl to talk back. That may also enable sub topics related to the active main one.
Depending on your answers and Maki's fondness (arrow gauge at the top of the 2 vertical bars or the left), you may be rewarded with either a "red heart" or "blue diamond".
The hearts/diamonds will appear in between the aforementioned vertical bars.
Tip:
Looking (1st. button on the right menu) at the girl's face tinily boosts the fondness gauge (Can't understand the logic in that though).
If you want 3 hearts, take your time maxing (all the way to the right) Maki's fondness toward you.
To enable Story Mode (suto~ri~ mo~do) 2 you'll need 3 (max) blue Diamonds (talk about Maki's boyfriend) while getting 3 (max) red hearts will enable Story Mode 3
To enable Extra Mode (ekusutora mo~do), which is Story Mode 1 but with Maki's obedience? (right vertical) bar maxed, do:
1. In Story Mode 1 to raise said bar as high as possible;
2. Rape her. Don't know how many times are needed, just be creative.
3. Advance through the 3 topics, talk back and sub-topics until you enable the bottommost (with red text) one then click there.
That should also unlock the 1st. (Domination?) end.
The Pain (itami) end as well as the Love (Rabu) end need you to start Story Mode 3 which is round 2 of the 1st. one.
In there, once more you'll have to choose among 3 independent topics, talk backs and sub-topics (this time fondness gauge is automatic).
Picking the right choises will get you up to 3 hearts/diamonds.
Pain End, get 3 diamonds
Love End, get 3 hearts
Click the bottommost (with red text) topic to watch the end.
Lastly, the Lewd End (which is the only one I had to look at the game readme file to figure out):
Start Story Mode 2; Rape the girl 3 or more times making her cum (bright red face along with "chupa-chupa" sounds while doing her).
Side note:
Regarding complexity and translation, this game is faily "gentle" Japanese wise. In fact, I myself got surprised at how far my basic (JLPT 3) Japanese knowledge got me.
I can't say for sure but, IMO, the challenge in terms of translating this will be more about "text amount" rather than "Japanese complexity".
I could give it a try but, since my last atempt with the "Miyui Swordswoman" was fully shotdown as "posing", I won't bother.
End of Side note:
