Raw: https://e-hentai.org/g/668633/b12c52ec35/

The irony here is that this a harem doujin with half the size of the actual canonical harem. Or probably less than half at this point.

Base +7, Amakawa_Yuuto +11, Britannia991 +6, sgc_geh +8, Xavier Blitz +7, ulgaming +6, shadow king +6, Zantos +6, XionXIV +7, UnknowDestroyer +7, AntiShisno +7, GabrielTDO +6, zzl4100598 +19, and 11 more...

For me they are the only ones that matters

The rest is just decoration to Issei's arms or lap

Base +5, naughts -6, Zantos -6, Alteisen Riese -7, Godoffire -6, Hue_Hue +5, Obscured Visage -4, satellitea -8, LegoArielFanMaster -8, いちゃ -13, lenzen -8, SirTwenty7 -4

If only the publishers would let the ending be even close to this. Issei earns his harem, all of the girls are happy, and the devil race gets a major boost in numbers from all the pregnancies. It would be the best harem ending of all.

Base +8, zzl4100598 +19, AnimeLov3rxXx +10, ThanatosNebula76 +7, Godoffire +6, Nitramy +6, Denys-kun +6, sable1 +16, IaY +6, Kiranta +6, see-eff +6, anonymousMember +6, SirTwenty7 +4

To me Rias is perhaps the least interesting heroine in the series, character wise most of the other females are much more interesting than her. I hope one of these days will get to see some doujins featuring 3somes with any combination of Asia, Koneko, Akeno, and Kuroka. Heck I wanna see one with Sona Sitri while I'm dreamin.

Now aside from my personal gripe, is there anything glaringly wrong with this doujin, other than what 7th circle mentioned?
Not really, though I would note that Asia and Koneko don't feel suitably in character so that might be a turn off for some but otherwise this is really good.

Base +6, kaiton -7, Obscured Visage -4, satellitea -8, LegoArielFanMaster -8, sgc_geh -9, SirTwenty7 -4

Koneko has a rather optimistic bust here.

Base +6, satellitea +8, SirTwenty7 -4