Just gotta say one little thing: This guy was supposed to be an adult in his past life, right?? Or at the very least a teen... So... Why is he so damn childish?? Either that or he is an idiot, because he seems almost completely incapable of understand that he has way much more power than everyone else, and even then it seems like he always makes stupid conjectures, like thinking that using the most higher lvl magic would be expected of someone of his "age", or thinking that a barrier that was put by mostly "normal" (by that world standard) people would be capable of resisting an attack like that.
Sorry for the rant, but this is the first time an Isekai MC has managed to make me think like this, even why I normally would never try to put much common sense while reading this kind of story (and I read A LOT of Isekai).
PD: Please, if someone is thinking about telling me to not read this if a dislike it, or something like that, then please refrain of doing so. While the MC did make me rant, just that is not enough to make drop a manga or novel.