These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Broken Base: The ending has pretty much split the fanbase in two. Some love it or at least accept it, claiming that Kimi's fate was properly foreshadowed, that it was what the entire story was building up to, and that the story really couldn't end any other way. (especially since the final battle is based heavily off of Thor and Jormungar's Mutual Kill in Norse Mythology) Others hate it, claiming it completely contradicts the theme and tone of the story, that the manner of Kimi's death comes off as cruel and/or meanspirited, and that it portrays a Family-Unfriendly Aesop of You Can't Fight Fate.
And now Kimi's resurrection has caused a more subdued, but still significant break. Some are pleased and even overjoyed by it, while some accuse it of being a copout.
Earlier than that, Maya's Face-Heel Turn was also a point of contention for many. The supporters saw it as the (somewhat) logical conclusion of a young, naive girl whose entire worldview has been shattered by a newcomer, and her desperate attempt to restore the status quo. Detractors claim that the logic is flimsy and that it flanderized Maya's character flaws.