No, not 100% negative; more or less, it's about 95% negative, mostly because he's not stating which elements of the story should be improved on.
But that critique makes an implication I find. First, he said that there's "bad detail". In other words, show your readers the story, don't just tell them (basically, add more detail so that an image may form).
Also, since it's "unoriginal", you will have to make the story more unique. For instance, a kid goes to the lab to get his starter Pokémon and afterward he leaves his hometown to battle, train and catch Pokémon as well as compete in the Pokémon League while stopping the bad guys from taking over the world. Boring and definitely unoriginal. How would you make it more original? If it were me, I would have the kid NOT be interested in going off on a journey but then he's asked to go somewhere and then a series of weird events unfold, which results in him competing in the League, despite the fact that he doesn't want to, and the bad guys could be random guy hunting the kid down.
As for "The main character is late, doesn't that remind you of a certain ash ketchum?".... Okay, I don't get the 'late' part but, basically, give the character his/her own personality; don't make him/her similar to any other character.