Slightly below average game, I'd say. Maybe a 2.5-2.75/5.
There's no story. She's down to mess around immediately, which to me is a con because I like a slower burn/corruption kind of thing, but that's not what the premise of the game is (she literally offers favors for money) and there's no corruption tag, so I can't really hold that against it.
Art/visuals are fine, but the low res (can't change) and censorship hurt it. Can't fullscreen the game (to my knowledge) unless you use some other tool like Borderless Fullscreen.
Gameplay loop is even more basic than other Imouto/Sistercest games on this site - tedious, but not overly so, in my opinion, so there's that. Very limited interactivity during H-scenes (of which there are 4, some of which have subvariations), which for me was the nail in the coffin (at least they're animated, though, albeit a bit crudely).
All in all, I expected more from this game given its premise and that it's Japanese (you'd expect it to be pervier given the kink and how into that they are, but alas...).