It's a fun story. Kazuya is a pathetic guy, I want to punch him in the face, but after 15 chapters, he becomes a pathetic guy who worthy to be MC. The story becomes more fun after Kazuya forgot about Mami, an ex-girlfriend who dumped him.

The art is good, the story is good, the characters not really 3-dimensional, but not without personality either. Some trope in this story handled very well, and there's a definitive progression in the story.

About Ruka. Ruka could be the best girl in this story, but shame to the author to handled Ruka this way. Her motivation to love Kazuya is kinda shallow, and I hope Ruka can properly like Kazuya not just because of her heartbeats. On the other way, (it's kinda spoiler) the progression of Chizuru, when she began to love Kazuya, is really great.