The first five episodes are quite enjoyable, and I especially enjoyed the commentary on the relationship between personality and body and the impact this has on how we perceive ourselves, and how others perceive us, and what happens to our personality once we become disembodied, or our body becomes malleable.
However, these ideas are quickly cut short by Heartseed, who abruptly brings the arc to a conclusion, because he's bored apparently, and therefore we now get another supernatural trick/gimmick to learn about and overcome. This does initially make the series feel gamified, and disjointed, and I wonder whether building up or adding layers of supernatural gimmicks may have worked better, and ensured that the interesting philosophical questions that were being raised in the first arc could have been continued, rather than being cut short.
It becomes clear as the series progresses though, that each of these gimmicks, at least as a plot device (and not strictly narratively speaking), are used to explore different parts of each characters personality and back story, and in that respect are a neat way of doing so - even if its at the expense of sequential cohesion. And because of this, its obvious that the themes explored in the first five episodes were supposed to aid character development, rather than put forward substantially any such philosophical discussions. This, therefore, isn't an ideas-show, but rather a character-driven show, and we are here to witness how these characters grow.
Even though each of the gimmicks are distinct, they do actually provide a nice through-line for each of the characters, leading up to a fitting crescendo (although I was never fully satisfied with these) at the end of each arc, and especially in the final arc. And while the final arc does seem to conclude all of the backstories, it doesn't actually wrap up everything - without touching on the complete exemption of Taichi having character development - such as who is Heartseed really, and why has he been doing these things to our main characters.
However, these questions may be answered in the OVA, which the final episode teases.
