Eromanga Sensei is an excellent show, but not universally accepted. It has the following... ah, features.
(a) it's Tsukasa Fushimi's "little sister incest" follow-up to Oreimo, which might be the definitive "little sister incest" series. I'm pretty sure it's the most commercially successful.
(b) it dodges one bullet only to embrace another. Oreimo's Kyousuke and Kirino were blood-related. This show's Masamune and Sagiri aren't... but he's 15 and she's 12. (Absolutely nothing happens, but that's still enough to trigger a red flag for lots of viewers. Furthermore, Sagiri's a gifted professional artist who specialises in filth.)
(c) it follows the standard light novel pattern of a male protagonist and a female supporting cast who fall in varying kinds of love with him. I couldn't argue if you called it a harem show.
That said, though, it's also charming. Tsukasa Fushimi's a strong writer who's unfortunately chosen to hang a "kick me" sign around his neck with his choice of subject matter since 2008. The cast are likeable and involving, making you want to keep watching them. Their decisions feel true to the characters and there's no idiot plotting. It's often funny. The show's utterly and completely platonic, which is of course all-important with Masamune and Sagiri. Finally, it's superbly animated (especially the character animation) and I love the theme songs and Sagiri's dance in the opening credits.
The TV series was broadcast in 2017, so these 2019 OVAs are a very short Season 2.
13. ELF YAMADA'S LOVE SONG
I love this episode.
Elf loves Masamune, but she knows she can't win against Sagiri. This is both a harem cliche and potentially painful. (She's also intelligent, by the way. She's got a monster ego, but she's not the kind of idiot who goes around deluding herself.) This episode explores her character, dissecting her feelings and motivations... and makes it funny and triumphant.
Elf's publisher is holding a publicity event for her. She wallows in it, of course, with thoroughly Elf-like bad behaviour. She's been telling her mother a load of porkies, for instance, which puts Masamune in a bit of a spot when he finds out. Mum appears, you see. Whoops. However there's a twist when she turns out to be a dinosaur. "I'll be the one who chooses a suitable husband for you."
I rolled my eyes a bit at this, but: (a) mum has issues of her own, and (b) more importantly, it's challenging Elf on the gross inconsistencies in what she's saying.
There's an important conversation under a table. "She's your family, after all." (That's a big deal for these people. Masamune and Sagiri are orphans.) Then, ultimately, Elf turns her reply into a public song-and-dance number. Band, spotlight, editorial assistants as her back-up dancers... is it realistic? Hell, no. Is it brilliant? Yes.
14. SAGIRI IZUMI'S FIRST KISS
If this were live-action, you'd call it a bottle episode, i.e. just the core characters, in one location. Masamune's ill. Sagiri shoves him into bed and takes over the domestic duties at home. Unfortunately, she's a hikikomori who wasn't even capable of leaving her bedroom when the series began. Just walking downstairs is a little triumph, which she celebrates with a "to!" and her arms raised like Charles Atlas. She can't order a takeaway, because she'd need to open the front door to collect it. (She can't cook either.)
Other characters appear briefly, but don't get into the house. "I'm not in." "We can see you, you know." Muramasa in particular kept making me laugh with simple scenes that theoretically shouldn't be that funny. (Both the animation and the music contribute.)
It's an amusing episode, but it quietly sneaks in more serious material for Sagiri.
In summary, both episodes are good. I'd love to see them continue with a full Season 2.