Fantastic idea, second-best execution. I enjoyed it and I'm looking forward to the OVA that's coming next year, but the writing really isn't very good.
Yet another hero goes adventuring in a wish-fulfilment fantasy isekai world. He has armour and a sword! He has beautiful female companions! He has monsters to defeat and treasure to collect!
Unfortunately, his mother's travelling with him too.
This is a brilliant idea. This is one of those shows where you spend twelve episodes laughing at the premise. It clearly got greenlit based on the idea, not the quality of the writing. (The original light novels have sold like crazy, incidentally.) I don't think there's any story, anywhere, that couldn't be made funnier by adding someone's mother to it. ("Darth, dear, I don't suppose you managed to ask Mr Palpatine if there's anything he'd like for his birthday?") What's more, this is a parody.
1. It's spoofing the modern isekai genre, in which there's no meaningful challenge since the hero is ridiculously overpowered from the start and can't stop gaining new abilities, weapons and magic items. (Masato's mother, Mamako, is the overpowered one, whereas everyone can only trail pathetically in her wake and complain that she keeps insta-killing all the monsters before the ostensible heroes get a chance to do anything.)
2. It's semi-spoofing anime's fondness for incest subtext (or worse), because this time it's worse than "sister". Neither of them is interested in anything like that, but Mamako is young-looking, sexy and the occasional perpetrator of fanservice scenes that distress Masato. They also do things like having public baths together. (I say "semi-spoofing" because there are anime fans out there who take it seriously, either reacting with gross-outs or with disturbing approval. Or jokes. Plenty of jokes. Sometimes involving Alabama.)
3. It's also semi-spoofing anime fanservice. The genre awareness in the hot spring scenes is actually quite funny. However that's basically garnish on top of fanservice that's being delivered straight, to the extent of light beam censorship and the possibility of nipples on the Blu-rays. (They haven't been released yet, so it's anyone's guess how far they'll go.)
That's just the idea, though. What kind of show has resulted from it?
There's a lot I like here. Even the worldbuilding is funny. It's an MMORPG isekai world that's been deliberately designed to be broken. It's mother-centric. Everyone's here with their mothers (with the mysterious exception of Porta) and the game's purpose is to nurture appreciation and love of them. In reality, all your players would probably rage-quit at being reduced to pointless tag-alongs... so of course the game doesn't let you do that either. You can't return to the real world unless you've improved your relationship with your parent. Mind you, the game's definition of "improved" is flexible. Masako and Mamako get close and yet aren't allowed to leave (thanks to self-serving cheating bastard game administrators), whereas, say, Wise and her mother are deemed to have cleared that hurdle despite going from "mutual hatred" to "still basically hostile and bickering, but with one brief superficial moment of Badly Written Attempted Heartwarming".
It's broken... but that fits, because it's by the government and it's only a beta version anyway. Mind you, in a mother-centric game where "mummy" is synonymous with "superhuman god-level object of worship", what's the purpose of ep.2's fabric-dissolving slime attack that only affects women's clothes? One can speculate about what the game designers might have been aiming for, but there are some disturbing possibilities.
The show also has some funny jokes and visuals. The gigantic fishing rod sticking out of the ground in ep.9 is surreal enough to be amusing in itself, but it's also a pun on the Japanese term for "scamming", "trolling", etc. The wish resolution in ep.12 made me laugh. Medhi's evil side and the MMMMMORPG acronym are amusing.
However it's also clearly as good as it could have been. Sometimes it's just a missed opportunity, but sometimes it's flat-out bad. The main problem, I think, is that not enough thought has been given to making the show fantastic. It could and should have hit that level, I think. It wouldn't even have been hard. The central idea's so strong that you'd think it would almost be harder for the show not to be brilliant. They just needed to put more work into the characterisation and create a cast that's more like KonoSuba than, well, the bland stuff it's parodying.
Unfortunately Masato is basically the default reactive comedy protagonist, without anything distinctive to make him funny in his own right. He's embarrassed by his mother, but the embarrassment is one-sided and nothing he's said or done is ever a factor in it. He's the Generic Vanilla Protagonist, basically. He's still okay and the show's amusing, but he's the biggest missed opportunity.
As for the supporting cast... Porta is a complete null. (Nice and amiable, but a null.) Wise is okay, but Medhi turns out to be a bit of a one-joke character (although it's quite a good joke). Shirase, on the other hand, is a grating one-joke character who'd overstayed her welcome before the end of her first scene.
Furthermore, the show's messages can be clunky and superficial. Story arc villains are often Mothers From Hell, which is good, but I wasn't convinced by all their eventual reconciliations with their daughters. The worst is ep.8. Medhimama's treatment of Medhi was basically abuse (at one point including sexual abuse at one remove), but with an intelligent, cutting observation underneath about mothers who use their offspring for self-validation. It's ultimately about themselves, not the child. Medhimama's emotional manipulation uses the techniques of real life abusers, e.g. making the child obey through guilt. There's a lot here to explore... but no, the episode throws all that away with the quickest, laziest shortcut to an emotional speech and everything being magically fine. Literally, it's magic. (This is then underlined twice over by Medhi turning out to be comedically evil in later episodes, which could easily have been linked to Medhimama and their toxic relationship. Nope, it's just a gag.)
Ep.4 works much better, with Wise's mother. The baddie makes some strong points, even if it does end in another reconciliation that can feel a bit thudding and unearned. I also quite liked the season's final story arc, which at least fits the show's tone in being very silly.
(Where's Masato's dad, incidentally? We never learn that. Mamako's dialogue in ep.7 suggests that she's not married right now, at least.)
This is a fun anime with good jokes, limited writing and iffy resolutions. Mamako is its not-so-secret weapon, of course, repeatedly subverting RPG cliches by being a loving, smothering mum. She's great. I loved her way of getting past golems and giant spiders, for instance. However it's also clearly no better than the third-best version of itself. The beauty contest in ep.7 can sod right off, the whole point of the fanservice is that it's gratuitous (e.g. the Censorship Sea Anemone with Naughty Tentacles) and the Naked Strategy Meetings don't become plausible just because Masato's lampshading them. There's an entire story arc where this becomes a school anime. The show's almost incapable of an emotional resolution that's not superficial to the point of being eye-rolling, while the Masato-Mamako relationship is half-baked. There's almost nothing there! It's okay, though. The whole show's okay. It's not very good, frankly, but the core idea's so funny that I was laughing for twelve episodes anyway.