It is from the isekai genre, but nonetheless, people who think of it as a bad genre will probably find this anime quite good.
Good storytelling, good fight buildup, interesting mc and characters, and a nice concept. There isn't almost any harem, and at the beginning thr mc isn't THAT strong. So, it's pretty good. I mean, who doesn't want to see a slime in the form of a cute loli conquer the world?