Good character interactions, very funny and heartwarming moments. I love all of the characters in their own way there is something unique about them and as a group dynamic the different relationships, the romance, the high tier waifus. The animation and visuals are solid especially the magic. Sizilien is amazing, one of my favorite anime girls. The world-building is good, we get to see a few different nations and the different ways they run their countries with politics and stuff. It goes even deeper further in the manga but we haven't gotten that far in the anime yet.
The science based magic system is great, I hate when anime just has character's pulling abilities out of nowhere for no reason or explanation. This has been a problem in shield hero, at the beginning it was good we got to see the progression and what monsters gave him which abilities but lately Naofumi has just been pulling up new abilities unexplained. In kenja, they explain the abilities and how shin comes up with them through science like light convergence, wormhole theory etc. So Shin isn't just op for no reason or because it's a game and their character is op or because of genetics etc. like many other op characters.
The main antagonist had a really good backstory and an explanation for his motives which is rare especially in isekai. I like the villain group too, definitely the best villain group out of any isekai anime.
Aside from that it is just a really good self-insert anime. I like the way shin handles himself and the way he thinks, he's logical and not indecisive, good choice in women, always looking to improve himself and help his friends. The way he has completely altered this new world with his knowledge from ours is just awesome. He is just a cool dude, I feel that.
