It's quite a nice show. It's charming and has things to say, although it also has peculiarities.
Makoto's parents are going abroad for work, so they're sending him to live with his aunt, Meme. She lives alone. He's imagining a quiet life. Little does he know that Meme has an extremely strange daughter, Erio, who never leaves her futon, let alone the house, and whose existence isn't openly acknowledged even by her own mother.
More girls will appear, but they're all weird and/or childish. Makoto is the show's straight man and his thoughts give us a running commentary, as often from a Studio Shaft anime. The only female cast member who seems to have a double-digit mental age is the one who walks around town in outrageous cosplay outfits. (It's wacky. She'll turn herself into a fish with legs, or a white sphere, or a whale.)
The show's about quite a few things, but its more prominent themes include fantasies, dreams and giving up. Erio thinks she's an alien. Meme never stops flirting with Makoto and implying that he's madly in lust with her. Maekawa is addicted to cosplay. The late-arriving Yashiro wears a spacesuit, also claims to be an alien and might, possibly, actually be one. The evidence is inconclusive, but it's enough to challenge the deadpan, dream-crushing Makoto, who has a normal perspective on everything and gives up on things. He'd call it being realistic. He tries to cure Erio's delusions and prove that she's not an alien in ep.3, which struck me as alarming and potentially damaging but ended up being sort of magnificent. (In a suicidal way. He ends up in hospital.)
I liked the baseball subplot. There's an important annual game between the local town and country teams, where the winners can choose this year's site for a festival. In other words, this game matters. (To the players and local stall-holders, anyway.) Makoto lets himself get talked into playing weekly baseball games that are, in effect, a season-long build-up for that big final. He's not very good. He's not achieving anything. That's not unlike the situation that led him to give up on soccer as a child. He sticks with it, though, in an arc that builds up to a pretty cool climax in ep.12.
At the same time, though, this is based on a light novel series. We have a male protagonist and a harem of girls who like him, although Makoto certainly wouldn't see it like that. Who will our hero end up with? Answer: it's left up in the air, so you're free to assume whatever you like. As an array of romantic leads, though, they're odd. In descending order of immaturity, we have:
1. ERIO = who's so simple-minded and abnormal that it's tempting to conclude that there's something wrong with her. (Possibly some form of autism.) When the series begins, she's a severe hikikomori who's in denial of her own humanity and walks around wrapped in a futon. Imagine a sausage roll with legs. When she unwraps, though, she's beautiful and will sometimes wear clothes that subtly suggest she doesn't understand modesty (and that she has an irresponsible mother). Genre formula would suggest that she's the one who'll end up with Makoto, on whom she becomes dependent, but who knows?
2. RYUUKO = Erio's main romantic rival. Energetic, incoherent and never thinks about what she says. Like an eight-year-old in a teenager's body. She's nice, though.
3. YASHIRO = not in the romantic race, but definitely fits into the pattern of mad female characters. Might actually be a child, which would explain a lot. (This is anime. It's hard to tell anyone's age.) The only thing that might explain her eccentricity is the possibility that her deranged pronouncements are true.
4. MEME = has her 40th birthday in ep.5, but acts like a dizzy airhead and often seems to be trying to initiate sex with Makoto. He always brushes her off without a thought, although it's unclear why. (Age gap, yes, theoretically, but her character design is extremely young-looking and she's by far the show's sexiest character.) Makoto regards her mental age as six. Some of her loopy behaviour is deliberate and underneath it all she's thoughtful and intelligent, but how much does someone have to act like an idiot before you're forced to conclude that they really are one? One might also question her parenting choices.
5. MAEKAWA = refreshingly and astonishingly, she's sensible. You can have an intelligent conversation with her, if you don't mind her midnight cosplay excursions or the fact that she'll get dizzy and faint if she holds her arms above her head for ten seconds.
It's an interesting, mildly strange series. (It's also set in Nagoya. There are scenes that I'm convinced are based on places within walking distance of where I lived.) I quite enjoyed it, but I don't know if I'll ever rewatch it. You'd have to examine the show carefully to see what its story arc is, or indeed whether it has one. It progresses more in terms of character growth and thematic exploration than in actual plot. Also, Makoto's inner commentary makes it feel slightly distant and self-aware. It's likeable, though. Sometimes it's funny. I'd give it a tentative recommendation.