A 1 star rating means I had better start with pros:
1) No Engrish. The writing seems by a native speaker, and despite a lack of decent plot or deep dialog, still seems coherently written. Let's face it, that's a bar some games (worth more than 1 star) fail to reach.
2) Graphics. I see little I recognize from other Ren'py games. That, if nothing else, speaks to effort.
3) Nice renders with attractive girls and realistic proprtions.
So, cons?
1) No meaningful choices whatsoever. Other than peeping on your mom, I don't think there is a single choice in the game. That means... it isn't a game. No alternative scenes, no branching paths, nothing.
2) Behavior makes no sense. From peeping on mom, to squeezing your sister's ass, to being OK taking your sister to a party where the entire purpose is to get laid.
3) too much, too fast. Dialog moves along and is done. Next scene. Click through a plot event with too little dialog to develop characters or story. Next scene. Camping and a party, with people you have never been introduced to, in a perfect opportunity for the DEV to flesh things out with longer scenes, more banter, even choices that could slightly alter what happens, but nothing.
Next scene, some decent sex renders that are too brief to even be tittilating, then you bone your sister.
The flaws of this game are ALL fixable, in a way that would make the game go from 1 to 5 stars, at least in my books.
Add some character content, so we know who each person is, and with mom, and both sisters, a little more dialog to establish their relationship. Why is MC so close to his mom and one sister, but Lilly states "we were never close to begin with" when worried they might drift apart? There is nothing until that point that indicates they are NOT a close family.
Some choices. In dialog, at home, with Mark at coffee shop, when shopping with sister, and at the party. Even if the game doesn't branch and we just get some dialog changes, it gives a feel for the personalities of the MC, who they're talking to, and a chance to add other info as needed to develop plot.
An excuse for why MC peeps on mom. Any excuse. Dude obviously creeps on his whole family. Some internal monologue at least explains how long he has done that, if he feels conflicted about it, and whether he straight up pervs or if he feels something for them.
The party. Perfect opportunity to flesh out characters. The chiche "truth or dare" scene. A playable poker where you could change the outcome. Extend things so it doesn't feel so rushed to see MC bone his sister.
For people who like a mopre "romantic" feel towards their games, or want the girls to be less slutty: make it so the party set up is said to be among friends, who trust each other, and while the hope is "we'll get a little lucky," that they expressed reason for the party is to have fun.
Besides, it feels more organic to have a party where things go a little nuts, and they pair off, then have the plan from the get go be "break into pairs and get laid like we're desperate middle aged people at a key party."
This also makes it seem more normal that 2 guys didn't get any and one just got blown (the girls knew the party was to get laid, as written, so that result seemed weird. Were as if it was just a party were people got frisky later into it, it makes more sense for some of the girls to not go all the way), and it makes it less creepy like the MC brought his sister to a potential orgy.
The scene where Amy and Donna encourage Lilly is kind of weird. Again, that could be written more naturally. Example: Donna teases Lilly, but then says she sort of wishes she was lucky enough to get MC. Amy agrees, say's she dating someone so won't do much tonight, but MC would have been tempting. Lilly does typical "that's my brother, that's gross!" spiel, and the girls all laugh. Amy, refering again to her relationship, just jokes "what happens in the tent stays in the tent, dopn't worry about it," and Donna gently encourages, when they're alone, that Lilly not worry and to take a risk if the mood strikes her, and that Donna won't judge her for it.
Is it realistic? No, but it works for a porn game, and lets what happens next seem more natural.
OK. Last bitch?
This whole "game," because of lack of choices, minimal dialog, and short scenes, plays in less than 15 minutes.
There is a plot that can be worked with and expanded to make a good porn game. There are attractive and unique characters. There is an MC who (so it seems) cares for his family and doesn't think only with his dick.
And there is moderately competent writing behind it all.
If the Dev chose to expand on what is here, now, to flesh things out and make what happened so far feel more organic, and moved forward into a story with choices, consequences, branching paths, etc? This has everything it needs to a GREAT incest/porn game.
But as it stands, without branches, without choices, without much dialog... and with the scenes we have seeming forced and not natural? The game deserves a 1 star.
I would be tickled pink to come back, once it hits [revised] version 0.5, and see enough changes made to justify bumping up my star rating, to 3 or 4. But I don't expect it.
A caveat however?
When working on my own game ideas (that will likely never come to anything), I've focused on a single, established plot first, and then sought out where to make the branches. Maybe dev is doing the same, where the core story is laid down, and they will go back, flesh it out, and add branches later. That's my hope. And if that is what is being done, because writing and coding for the central story is fastest and easiest, and they plan to flush everything out after, then my rating is unjustified and it should be a 4/5 game. But if that is the approach, dev should also say so, so we know to expect things to be revised and fleshed out further, later.