This looks quite promising. I can't say anything about your coding work so I will focus mainly on the design and a little bit on the story.
Let's get my opinions about the story out of the way. As you stated, there isn't much of a story. There is only 2 choices that are story-related, and they don't seem to ahve an impact on anything since you get the same text and ending no matter what you chose. The characters' reactions and personalities are consistant and realistic though, for instance the main character had mixed feelings about incest at the begginning, yet at the end he doesn't want her to leave. That's something you should keep in your next games. Btw there is some typos in the beginning of the game, some "i" in words are replaced with "I'm", for examble "I'magination".
Now let's talk about the design. The 4 models look pretty good and their positions while doing basic actions in the CGs are realistic. The animations don't make my potato pc lag, unlike ICSTOR's Milfy City which made me lag on some of his', so I guess it's a good point.
The characters' looks are stereotyped, and that's not a a bad thing. To me, it will throw you out of the story if a character doesn't look like what it's supposed to look like, for example you will never see cops wearing Kigurumi in a serious story. The same goes if the MC looked ridiculous or unfriendly, if the fashion photograph looked like she was wearing garbage, if the mom looked like she's 12 years old or if the aunt didn't look attractive.
That's something you should keed in mind in your next works, especially for the main character. Why do you think the main characters in harem/reverse harem anime looks so average with an average personnality ? Because the viewers will be more immersed in the story.
The only criticism I have to make about the design is that the expression on the aunt's face doesn't change no matter how hard you fuck her, but that's a pretty minor point.
This is a well deserved 4/5, pretty solid for a first game, would have gotten 5 if not for the few mistakes here and there. If you've read that far, sorry for my bad english lel.