This volume is an improvement on the first, in a couple of ways. First, the T&A has been dialed back quite a bit, and isn't as much in the reader's face. Mayuzuki is no longer making sure that Reiko's boobs are a major factor in every single panel featuring her, though of course her design remains wasp-waisted and long-limbed, and plush everywhere else. We've got a plot! and I don't really know where it's going.
Reiko has gained a female friend, Yaomay, who the reader met briefly in the first volume. They share a love of sweets, which maybe isn't the firmest basis for a relationship. So far much of their non-sweets conversation has been about Kudou, or the growing mystery surrounding Reiko. I theorized that Yaomay might be trans because she talked about having had extensive plastic surgery, but my partner who's seen the anime says that there's another reason why she wanted to change her appearance.
Reiko comes across as rather naïve about what effects her actions might have on Kudou. She wears a pair of earrings similar to the ones "Reiko" was wearing in the photo she found in Kudou's desk, which unnerves and irritates him, leading to a "silent treatment" argument. They reconcile quickly.
Lipstick and possible corrective treatment for Reiko's crow's feet (as much as I disagree with his behavior as a doctor [to say the least!] I agree with Dr. Hebinuma that crow's feet are not a major concern in your early 30s) both cause contention between our would-be main couple, and point toward Reiko's amnesia, or even toward her existence as a newly created being. She doesn't have a strong idea of what aesthetic she likes best for herself, and largely is guided either by Kudou's taunts (eff you, buddy) or Yaomay's encouragement.
A lot of Reiko and Kudou's interactions are about food, too, come to think about it. Reiko is fond of strong flavors: the sweetness of watermelon juice, the tartness of lemon chicken. This isn't a foodie manga, but it's nice to have details like this to help immerse myself in the setting.
Dr. Hebinuma is suitably creepy and, like many other characters in the story, has an outsized interest in Reiko. Storytelling with a single character as the center of the worldbuilding, and most of the cast trying either to support or thwart them, can be trying. I can't say I'm super fond of anybody in this story, including (or especially) its evident ML. But the art is quite nice, and I'm intrigued enough about what's going on with the doppelganger element of the plot to keep on with it for a while longer.