Thank you for this.I think that the game is mostly excellent, and does a good job establishing the dynamics between the various characters. Language was a bit rough in a few places, but better than most games, including some written by native-English speakers. Some of the characters are a bit "lumpy" (big muscles don't look like that) but there are no freaks. People look their ages, which is refreshing. Tits are big but not torpedo-sized, also refreshing.
One of the things you should avoid is using the word "moan" as part of the MC's involuntary dialogue during sex. No one says "moan" when they moan. Just have her go "mmmmm" or "ooooow" or something to simulate the sound of a moan.
The game jumped into sex and kinks pretty quickly, but that didn't seem awkward. The attempted rape seemed a bit out of the blue, and the teenage kids were definitely not acting like teenagers around each other in the shower (they are no way going to take a shower at the same time as that, both being too insecure to let the other see them naked), but that's probably not a concern in a game like this.
This shows a lot of promise. My congratulations to the dev. If I were to have a voice in this, though, I'd tell you to generally stay away from the whole incest angle. That's been done to death and I think your story would be better if the sexual tension between family members was centered around shame rather than lust. There's plenty of other sources for lust here, and having a realistic family dynamic would make your game stand out.
Yes, my language is a bit rough, as it is not my native tongue I am not ashamed of my level, but it clearly need work, so please do not hesitate to correct me when you see something.
On that register I have a problem with onomatopoeia, each language has its own set, and I am quite lost for the english ones, the english I use in life is very conversational, not much occasion to see some written, and the "moan" one is one I was not happy about, I will change that.
For the incest part I hide the answer for those who do not wish to see spoilers.
On the incest part, it will be a possible path for the main character, but it will be far from being the only one, there is multiple strings of events that I have in mind with the son and daughter, some about love, other about lust, and there will be some just as mother and son or daughter.
I want to offer the player a lot of possibilities in the game so there will be a lot of possibles paths, that will intermingle, that you can follow or not.