Alright... Turns out that once you fetch yourself a half decent translation of this game, it ain't so bad.
I did not ever expect to rate an AI-generated CG game this highly, but the developer clearly took loving care of this project. The UI is non-default, and fits nicely within the context of the AI images. And the AI images themselves were carefully generated so that each character had its own matching set with no mismatching images.
Of course, the game would have been elevated had it featured human-made art instead. 'Cause you still see missing fingers and bent limbs here and there. But if you overlook those imperfections, you'll find that the game is decent and fairly enjoyable.
The battle fuck could have used some more attention though. It is very easy to end up unbalanced and OP once you hit your stride with money earning. And the while consecutive battles could have been a good idea, the fact that the first encounter is always against a low level, and you need to fuck/battle her like 5 consecutive times or more before she gets to a level were she can match you, makes it very repetitive. That plus the fact every battle begins with a couple seconds of penis insertion, makes the consecutive battles concept tedious after a while.
The story pacing gets a little weird if you don't follow Nanana's instructions right after receiving them. I ended up maxing out my GF's favourability and corrupting 2 of the rivals before TS-ing the third, and upon doing so, Nanana's like "okay, now get your GF's favour to 500" and I was all "Okay? I'm already at 1000". Taking on one rival at a time trivialises a lot of their threat. So I'm not sure you're expected to do so like that.
Basically, those are all my complaints:
* Pacing can get weird.
* Battlefuck gets repetitive after a while.
* And the art would have been better if human made.
But, overall:
* The game is entertaining.
* The premise is good, and the writing sells you decently enough the experience of having a relationship and caring about your GF.
* And the gameplay loop isn't too bad either.
A rare AI product that isn't effortless trash.
(For anyone wondering, I used the translation file provided a couple pages into the thread by another user. Look for it. This review does not reflect the default MTL offered on the main post)