Tsuujou Kougeki ga Zentai Kougeki de Ni-kai Kougeki no Okaasan wa Suki desu ka? Namiuchigiwa no Okaasan wa Suki desu ka?

I'm really not sure what people expected out of this OVA or why they'd expect it to be different from the show. It's an OVA for a series which plays on very overt incest themes and otaku escapism.

Okasaan online does not pretend to be deep, philosophical or substantive, and the OVA keeps that same vibe. It's a fun, silly and relaxing OVA beach episode with the same level of humour, antics and action that we saw in the series. If you did not like the series, you will not like the OVA. If like me you enjoyed the show, you'll love the OVA. It's ... a fun time and has everything we enjoy about this series dialled up to 10.

Again, this is not an amazingly written episode nor does it pretend to be. Go into this for cute girls and fan service. If you do, you will have an enjoyable experience. If you're not ok with otaku escapism, incest vibes, lewd comedy, etc., steer clear of this.

Personally, as someone who loves the series I found this to be an extremely satisfying blast from the past(summer) and look forward to more content from the series/LN.

Okasaan online OVA gets 10 Shirase's out of 10.

Story 5/10
Art 5/10
Sound 5/10
Character 5/10
Enjoyment 6/10
Overall 5/10

First we can see how a beach chapter will be like any other.
Everything starts normal with Masato with his harem and his mother, then a couple of unforeseen events happen and the fanservice will not be lacking. Until the point of feeling a very incestuous relationship comes, but then everything ends well and there is no incest.
In conclusion I highlight the good atmosphere and a quiet and average OVA like any other OVA on a beach.
...
In addition to an almost incestuous ending and that the girls get amnesia, I highlight the kraken that appeared, that kraken is perfect, it has tentacles, skin, eyes, it is perfect.

"Araara mama, ufufu no mama, Mamako desu"

In this beach episode Mamako finally gets what she wants, but not really. Masato was fooling around with that Japanese game that involves hitting a watermelon on the ground, as he was following Mamako directions he gets mad that when he senses a watermelon it is actually Mamako's "watermelon", he get pissed and throws his bat at the sea, but since karma is a mistress the bat is thrown right back at him and Masato loses his memory. Despite having an harem, Masato ignores them and his eyes are focused on Mamako and he starts to develop some ... Oedipus-y feelings - and fanservice was there for Masato as well -, which our pure Mamako doesn't see with any ill intent, she even feels so happy we he says that he loves her. He then in a snap regains his memories and this special ends with his party members losing their memories and Shirase dying. Overall, it is an episode with several moments and aspects shown on the show.

Art is poor, rarely they put effort on drawing bodies, faces, clothes- who am I kidding, there were only bikinis here -, it is just a lame job. Animation is quite limited as well.

OP is quite good, it was awesome to hear it again, the ED had a small portion cut, there are those moments when Kayano Ai says as chibi Mamako "Mamako desu" and "Arigatō" and they are barely audible, which is a shame.

It is the same beach episode you probably watched in every other seasonal anime, you will probably watch it for Mamako; Porta, Wise and Medhi are there for appearance's sake.