TL,DR: A cute slowburn bro x sis romance that could do with a lot less grind. I also really wish it wouldn't ruin its side-characters moments after introducing them.
The main romance is between the PC - dumb as a brick but with his heart in the right place - and his sister, an (initially) nerdy bookish girl who reads Tolstoi in russian and quotes Sun Tzu in everyday conversations.
I'm of two minds on this one.
First the positive: this game does a really good job showing a slowburn, gradual seduction. Scene changes are nuanced, PC and sis slowly change habits and get closer/more intimate day by day. Also butts. It has some really nice butts.
Changes are in fact so nuanced that the whole story might make a lot more sense as an Everlasting Summer scenario or Groundhogs Day loop. (By the third time the same exact outlandish scenario happens, i would suspect someone is gaslighting me)
You could call the start of the story "immersive": after the first ~20 days I really believed the PC was bored out of his mind, because so was I. Okay, now we're primed to embrace some change.
Change comes in the form of Vikki and Helena. Here's the decision i honestly don't understand: why introduce two characters as alternative romantic interests, but make them almost immediately obnoxious and unappealing.
There are characters that are written to make the audience love to hate them. Those two are ostensibly likeable enough to justify their own routes. I'm sure a strong enough mom x son incest fetish can overcome Helena's annoying character. I couldn't.
Choices then explicitly state something akin to '"that option you wouldn't pick in a million years because Vikki/Helena are obnoxious? Pick it, because you'll miss out on a bunch of content otherwise or just plainly can't progress the story". I appreciate they were clear about this. I'd have appreciated it more, if those choices were something we'd actually wanted to do, instead of being strongarmed into.
Eventually I got tired of the grind and being forced to interact with Vikki and Helena, so I dropped the game on day 53 (when you're expected to suddenly want to grab Helena's ass because the story won't progress otherwise, even if you've avoided her and told her to fuck off on every step of the way so far).
There is quite a bit to like in this game though, for people who are more patient and not bothered by Vikki/Helena.