While I'm not used to reading romance, I'll try to review this as objectively as I can.
First, the writing quality is somewhat shaky, especially toward the start. I noticed a lot of uppercases in the middle of a sentence, a lowercase at the beginning of some, and a rather liberal use of ellipses.
Still, it gets better as the story goes on, and there's a sharp increase in quality by Chapter 9.
Second, the updates don't seem that stable, with the latest chapter published eleven days ago. However, writing is hard, and I can wholly empathize with the author on this one.
Third, the plot develops at a reasonably good pace, even fast by some standards, but that's good in and of itself for this format. The story has a cozy atmosphere, something I could imagine myself reading in the comfort of my covers, which is the goal of most romcoms, I'd argue.
Fourth, the characters are the driving point for this book. They're expressive, anime-like (which isn't a bad thing), and all-around fun to watch interact among themselves, especially Koi and Airi.
Lastly, the world background is still vague up to the point where I stopped, but since it's a contemporary romance, I guess it's not and should not be the story's focus.
All-in-all, an entertaining read. I'm sure the author will get better with time, but his foundations are already solid.
