TL;DR: Very good writing but with a few hiccups here and there. Renders aren't great but are serviceable enough. There's actual music and sounds, so that's another plus. The one star review heavily exaggerates the whole zombie rape thing, there's only 3 scenes in the game about it and they're easily avoidable.
Alright first off let's get this out of the way: The whole zombie rape NTR thing. I honestly have no idea why it's in the game besides the dev just wanting to put it in there. At the beginning, this is never even hinted as a thing that can happen and they just start randomly showing up with cocks out halfway through the game. It doesn't make much sense and the dev throws a bullshit excuse to justify it after the fact. It just clashes with the rest of the experience and feels like it's there to appease the dev's fetishes. Game would definitely be better off if the time spent on those scenes went to literally anything else(especially because they're pretty long).
The writing itself is honestly great, especially for just a generic zombie plot. It's more of a slow-burn, that heavily leans into the taboo of incest. You're not going to be instantly fucking your family members(or at all as of 0.5), and that's great. It's really refreshing to see a more realistic take on the trope, and it feels like there are actual reasons they're interested in you besides just porn logic. It can be a bit too melodramatic sometimes with lines like,
"It took me a long time to get used to it you know, this silent world without the slightest sign of life, where death reigns supreme."
I get you're trying to set a tone dev, but jesus christ make it a bit more subtle, yeah? It's not too egregious though and it's mostly just a few lines that make it noticeable.
The MC is... mostly just a generic anime MC. Wants to protect his family, likes perving on girls around him, etc. He's not stupid, dense, or feels especially slimey though, which is a godsend to this site. His whole arc about wanting to protect the girls but being unable to is really played out, but it's one of the better examples of it so I can let it slide. I would prefer an outcome where he realizes he can help the girls out in other ways than just protecting them but I'm also a sucker for reversed gender roles so I'm a bit biased.
The girls look a little off but personally I think it adds to their charm. They're attractive, but not generic super models with 0 flaws in appearance and have realistic bodies. They're pretty well-written and aren't just your stereotypical trope "sexually frustrated mom" and "bitchy horny sister". Well they kinda are, but there's a lot more to them than just that. They feel like real people with their own flaws and reasons for doing things while also being charming. Same goes for MC. They all interact like a real family with all the ups and downs of one, you can really tell they care a lot for one another.
The porn writing however is just OK. It's not gonna turn you on a ton, but it'll get the job done and can be pretty good at times. Most of the gratification from these scenes is the sexual tension and taboo of it all, not really from the actual writing for the scenes. A very common trend for the dev is to compare the sex to something else. I laughed my fucking ass off when he compared MC's dick to the fucking TOWER OF BABEL.
It's also noteworthy to say that it's mostly the girls that take the lead here, both in and out of sex. Your sister and mother are better at fighting than you, mom calls you good boy, sis says you belong to her, etc. Personally I fucking love that shit but I can understand if it turns some people off.
The music and sound effects are just fine. Nothing to really write home about other than it works.
Overall, I was very pleasantly surprised by this one. It has a refreshing tone for an AVN, good multi-layered characters, and a nice slow-burn incest story. It's not going to get your rocks off as of yet, but I think that's fine. We need more games on here that aren't afraid to make the player wait in order to properly set things up for a good pay-off later.