Those that gave one star either haven't seen all 11 episodes or these type of Anime is not to their liking in the first place.
I have been watching since the first episode and it is nice to watch with a evolving plot with some good action involved.
Yes, the first episode was a young fat and ugly bullied and harassed teenager who due to entering a magical world was transformed into a very handsome and desirable young teenager.
But he didn't transform immediately magically. It seems like when he first entered the other world as a fat ugly teenager, he started fighting and training which led to his transformation into a slim handsome young teenager due to his intense training and fighting in the other world.
At first I thought this might be a Harem type anime which would have been a disappointment, but it seems like the MC is just interested in making new friends except for the first girl Kaori which he saved before the transformation. He does seem to realize that she still cared about him emotionally and not physically when he was still a fat and ugly young guy.
But it is possible that the MC might still end up with 2 wives eventually. One on Earth (Kaori) and the other at the Other World.
But so far I see a well written story with good animation and Action, Drama, Romance, & Betrayal and beautiful young females and males with strange animals with powers to boot.
Besides the normally good and innocent morals of the Japanese Culture concerning the opposite sex interactions of young teenagers.
I just hope it doesn't devolve into a Isekai Harem story. That would be disappointing.