Since I'm not familiar with the 'choppiri toshiue demo kanojo novel', it's difficult to say exactly. It might be a story that delves into the connection between two characters, perhaps with the male character being a bit older ('toshiue' could imply older age), and the story revolving around their relationship, which is common in many novels. But again, this is just a guess.
I don't have enough details about 'choppiri toshiue demo kanojo novel' to give precise similar novel recommendations. But if it's about relationships in general, you could try 'Pride and Prejudice' by Jane Austen. It's a classic that focuses on the relationship between Elizabeth and Mr. Darcy, exploring themes like love, social class, and family. Although it may not be exactly similar, it does deal with relationship - centric themes that are often found in many novels.
I have no information indicating that it is popular. There are so many visual novels out there, and without any prior knowledge or data about this one in particular, it's difficult to say it's popular.
Since I'm not familiar with this specific visual novel, it might be about different characters' relationships and the story might revolve around how they interact with each other in various scenarios. Maybe it focuses on the character 'kanojo' and her experiences with different people, but again, this is just speculation without more knowledge.
In my opinion, both have their merits. The anime has great animation and sound effects, while the manga allows for deeper exploration of the characters and plot. It really comes down to personal taste.
I'm not sure about its popularity. It might be popular within certain niche communities who are fans of visual novels, especially those interested in stories with female - centric characters. However, without more data on its sales or community following, it's hard to say for certain.
The domestic 'Na Kanojo' differs quite a lot from the one on Manga Rock. There could be adjustments made to comply with local regulations or cultural preferences, which can lead to a noticeably distinct product.
I'm not entirely sure specifically as I haven't fully explored it myself, but generally a visual novel is a form of interactive fiction. It might involve stories about relationships among characters. Maybe it's about different aspects of the relationships between 'kanojo' (which might mean 'she' or 'girlfriend' in Japanese).