Americans Hate Tingle: Although the show is the most popular in its season in Japan and had high ratings, some in many western countries dismiss it at best because of the author's past reputation and the pseudo-incestuous relationship between a 12 year old girl and 15 year old boy.
Even among Eastern audiences, opinions on the show are split. Many considered Sagiri less The Woobie and more The Scrappy because she kept demanding Masamune's attention without showing any gratitude.
Author's Saving Throw: It contains one for Oreimo. After the ending of that series made some fans fear that Kyousuke irreparably destroyed his friendships with Kuroneko, Ayase, and Manami to be with Kirino, The Cameo in the eleventh episode shows that Kuroneko and Saori, at least, are still friends with Kyousuke and Kirino after all that happened.
Awesome Music: It's hard not to like the opening and ending theme, especially when combined with a rather catchy video performance.
Best Known for the Fanservice: Many people are more aware of the harem cast and incest (and the pantyshots) than the major plot about the literary community.
Bile Fascination: Many viewers continued watching just to see how bad it would keep getting.
Broken Base: Is this a new, full-fledged work with an original storyline, or is it an attempt to retry writing Oreimo, removing Incest Subtext and the ending that angered many? As the adaptation began, this was accentuated as it repeats the style of the previous work, being made by the same studio and featuring an extremely similar art style.
Die for Our Ship: Fans of Yamada Elf are inclined to dislike Sagiri, as she is a fairly big hurdle for Elf/Masamune because of the series making the BrotherSister Incest completely obvious.
Fandom Rivalry: With Imouto sae Ireba Ii: fans of that tend to call this work exactly the kind of trashy Fanservice filled faux-meta light novel that Imouto sae Ireba Ii poked fun at, while fans of Eromanga-sensei consider Imouto sae Ireba Ii to be a pretentious, stuck up its own ass series that's really no better than the kind of light novels it makes fun of.
Fan-Preferred Couple: Although Sagiri certainly can be called the most popular character of the series and is officially its face, the Large Ham nature of Elf and the increasing emphasis on her accent in the anime quickly brings the Elf/Masamune pairing forward, at least among Western fans.
In a very obvious way with Oreimo, having the same author, BrotherSister Incest as a main storyline, the duet between Nice Guy older brother protagonist and the sister studying in middle school, etc. Moreover, both LNs have many references to Otaku culture. The main difference is that Eromanga Sensei is dedicated to unrelated siblings and an adjacent literature community plot.
With Imouto sae Ireba Ii/A Sister's All You Need, which also has a combination of Imouto with the theme light novel, however more oriented to the fanservice and the real Incest Subtext.
Fountain of Memes: Sagiri and Yamada Elf seem to be specially made for this, like the hot younger stepister and the crazy Large Ham rival, so they steal virtually every scene where they appear, and many of their moments are used as comedicgifs.
Friendly Fandoms: With fans of Oreimo and Himouto! Umaru-chan because of similar sibling and comedy plot settings, obviously. Although Eromanga and Umaru have different end results, in most cases, people who like one of these series will like the other. Fans of The Irregular at Magic High School usually also like this series because they both go out in one publishing house and have a powerful imouto-moe as one of the bases of popularity.
Genius Bonus: One of the reasons for the success of this series is the light it shines on the nuances of work on light novels, including a discussion of concepts and the creation of illustrations, which makes it quite popular among people from the literary and artistic community.
Harsher in Hindsight: Episodes 9 and 10 certainly do not reach Oreimo's level in this, but they are definitely perceived as very cruel when you see how the Elf and Muromasa express their feelings to Masamune and promise that they will achieve his reciprocity. Oh, it obviously will not happen.
It's hard to suppress a smile when Masamune says in one of the episodes that "older brothers do not represent vulgarity with their younger sisters." Yes, we believe the words Author Avatar of the person who wrote Oreimo.
Excessive efforts to justify the choice of Sagiri as the main Love Interest Masamune can be very amusing, if you take it as the author's attempts to avoid similar controversy that was around the ending of Oreimo.
It may happen that the interaction between Masamune and his father in the 11th episode will be impossible to take seriously because of Narm Charm, since it looks like the Tatsuya Shiba's care of a young Kirito. Moreover, Nakamura performs three roles in this show, including the cameo of two of his older brothers from other BrotherSister Incest series. The son clearly followed his father's way!
Nobunaga Shimazaki's role as Masamune comes as this, as he was the dub voice of Joffrey Baratheon, who was the product of an incestous relationship, and ironically enough, he is not interested on sex with anyone else.
Hype Backlash: Given the Moe nature of this show and its popularity as a source for memes, it's no wonder that the growth of its popularity has become the object of criticism among alleged purists from the anime community. Add to this the popularity of the original novel and the dislike of the incest plot among part of the Western viewers, and you will understand how mixed attitudes have developed about its popularity.
Internet Backdraft: A brief cameo in an early anime episode showsRuri Gokou on the TV, which wouldn't cause much fan anger except that she was wearing the same kimono as when Kyousuke rejected her, as well as saying she was at the festival alone. The Kyousuke/Kuroneko shippers who still haven't gotten over the novels' endings took that as twisting the knife and blew up on the web. However, a later scene showing that Kyousuke and Kirino are still friends with Kuroneko softened the blow.
There are also those interested in writing and art, and want to learn more about it. Since this show is pretty good about showing how such things work and are developed, it presents an opportunity to learn via watching anime.
Some think the 15-year-old protagonist developing a romantic relationship with his 12-year-old stepsister and discussing dicks with her classmate is off-putting. This becomes even worse because of the increasingly revealing Covert Pervert nature of Sagiri and her strange fixation on "vulgar" things. Eventually not all Western viewers would be happy to see how, for the purposes of "comedy", a 12-year-old girl pulls off panties or draws porn for her older stepbrother.
We never see Masamune telling other characters that Sagiri is not his blood sister. Nevertheless, even girls in love with him find their "Incest Subtext" as something self-evident and even support it ...
Win Back the Crowd: This series marked the return to popularity of its author, after the end of his previous work caused a scandal in the anime community.
WTH, Casting Agency?: Yuichi Nakamura as the father of Masamune. In most cases, when he played fathers, his children were still too small, because of what his voice sounds too young and his conversation with his son by ear is felt as a conversation between two peers.