There's really not much you can say. Different people like different things. Some want straight to H, some enjoy working for it, some enjoy the story along with the H.
For me personally, I love the MC.....despite how bleak this game and her situation is, she's very cute. Plus I enjoy platforming games. I have my pure H games, and I have games like this to scratch that itch when I play non-H games and think "This would be great as an H game"
Also you should NEVER rely on sales count to determine whether or not you personally will enjoy a game. Half of the sales could easily be people who did not enjoy the game. A few games I own have a few hundred sales at most, and are some of my favorite games.