@Misticsan This manga uses the isekai troupe to its fullest potential, the harem aspect every girl is likable and with their own personalities, the other world aspect that is almost a copy paste of ours but it feels alive and unique, even to overpower aspect here is well done as Kai has access to nearly unstoppable power but he has to have one of the girls close to use it, and as we have seen there are weapons that are capable of hurting him ( even if the can feel a little deus ex machina ).
All these aspects were thought out, every little piece fits its place perfectly, this here if I can be so bold is the perfect isekai and if any of you disagree with that i would love to know what you guys think it would be necessary to improve the story.