Yakusoku no Neverland is a manga that started great, then lost its drive for a mediocre middle part, picked up a bit of the steam for the later part with a different driving force for the interest but failed to do a satisfactory/interesting ending.
As mentioned, the first part is the best. Unfortunately the rest of the manga fails to catch up to the hype by both the first arc of the manga itself and by the well done anime adaptation of the said arc. The protagonists, the villains, the revelations, there is not a dull moment in this arc. One thing about the characters is that you have suspend your disbelief to accept that those very young kids are perfectly capable of waging Death Note-esque mind wars, but this is at least somehow excused by the setting being orphanage that focuses on creating extremely gifted children.
Regrettably, those engaging mindgames recede into the background as the next part focuses more on fighting capabilities and firepower. Some smartness is still included, but it can be abbreviated to running around, hiding and gunning down the demons while occasionally being hunted in turn. Or maybe the other way around. This is undoubtedly the weakest part that feels a bit repetitive and most importantly far from the uniqueness of the first part. It's still not bad, mind you, but it's still not exactly great either.
Now, contrary to the popular opinion, I don't believe Yakusoku no Neverland only went downhill. I, for one, enjoyed the demon politics, hierarchy and the power struggle between them. I also enjoyed the changes within a certain character that made them grow colder as they had to sacrifice their feelings for a personal good, which also helped to make a contrast with Emma and quite surprisingly made her something more than just a generic goody two-shoes "everyone must be happy" character. While she still is beamingly positive, it is shown that those are not just reflexive reactions and she too is willing to go to greater lengths for what she believes is the greater good. Emma wasn't my favourite, but this part certainly made good job of making the reader understand her closer.
The later part also has one of my most favourite moments in the whole manga to which I will refer as to a "dog girl" to avoid giving too much spoilers. It was one of the greatest twists in the series that really makes you feel and consider some other sides of the story. Reversal of expectations, in a good way. Compared to for example the final "villain" turning out to be a weird goblin with riddles who seemed to create the whole conclusion just for the lulz it makes out the uninterestingness of the ending stand out even more.
The finale just doesn't fit the mood. Heroic sacrifice that gets toned down to what is just a minor inconvenience in the context of the overall situation feels just like pouring boiling water on your ice-cream. I certainly expected some more ballsy ending than this. Emma is shown to be stubborn lawful good and for this to have a character pay-out her decisions should have their full consequences to give weight to actions she did to follow through with her belief.
Overall this is still an enjoyable watch that compensates for its weaker parts with the brilliant parts. You might not enjoy every part of it, but as a whole you'll most likely like it.
