Anyone read the LN? Mind typing out a short review?
I read LN 1 to 3 (not sure where that corresponds in the manga).
There's 6 girls, you get 3 in book 1, 1 more in book 2 and 2 more in book 3. There are 15 of these available in English so I wouldn't be surprised if there's eventually more. Up to Ch. 14 of this manga is translated and they're not yet through book 1.
The character setting is the same for all of them: he gave them superpowers and now they love him, unconditionally. They fight over main character Allen in every volume, for both instruction time with him and for his love. The situation was the same for all of them: at first indifference, then a tiny bit of success, which unlocks in their mind unconditional love for Allen and hard work under his tutelage (because said hard work will result in superpowers and who wouldn't sign up for that?). Harem queen Lydia's character setting is really childish: the world's most beautiful, powerful, and devoted young woman, and for problems she has boredom and (potentially) not being able to marry love interest Allen because of their commoner/noblewoman statuses, which aren't threatening problems. She's also her duke family's heir so you can add rich to that. I think she's easy to like because she's beautiful, powerful, and devoted, and she's confident too (confidence is sexy), even if she bothers Allen quite often with alleviating her boredom. A twist is Lydia is much more powerful than Allen (he has known Lydia the longest and made her this way because he is actually a decent tutor; usually the king is the strongest member of the harem) and for this reason she will be helping him solve the plot quite often. All the girls are hard workers, Lydia included, so that's something to like about all of them. I think they are all working hard for their superpowers for the wrong reason: so Allen will like them more. That's not how Allen sees it: he wants to help these girls reach their full potential.
In each volume you're getting a rising action, a battle scene near the end, and a resolution scene after the battle. I liked books 1 and 2 and I liked book 3 way less and dropped it. There is a myth arc (something going on in the background with the adult characters) but I got arc fatigue (lack of faith the author will ever resolve the plot) because the author took too much time getting to a resolution. Something about the reason Allen & friends are all way more powerful than the average person, like magic was deliberately made weaker by those in charge (for some unknown reason) at some point in the past. You have barely been told anything by the end of book 3 despite adults seemingly knowing, and not telling Allen and Lydia, who are themselves adults.