ChäoS;Child: Silent Sky occurs after the events of the anime series and for the first half focuses on Serika Onoe digging her way back to the New Generation Madness murders and to Takuru while the last half gives Takuru the resolution he gets after the bittersweet ending he was given in the anime series.
Oh don't get LA wrong, Takuru pretty much KNOWS he needs to take the punishment he created himself and he gets it both emotionally and latter on physically thus even the True Ending though a little bit less ambiguous as the anime series ending it's still bittersweet.
Due to the anime series ending, the only main players of Silent Sky are Takuru, Serika and Mio, with major character development in the form of resolutions from Takuru in fully owning up to his crimes from the anime series, Serika from knowing to stay away from Takuru and Mio guiding them in curing the Chaos Child Syndrome from the rest of the cast (thus their inactivity from this movie until the end). But even with the majority of the cast absent, both of Takuru and Serika's ultimatum was great development from them and again helped with the ambiguous ending the anime series gave us.
The animation and voice cast are back so LA won't say much, really the animation is expected from Silver Link, while Sumire Uesaka as Serika and Yoshitsugu Matsuoka as Takuru were probably the most obvious standouts with them taking the majority of the screentime.
LA will say that ChäoS;Child as an anime was a bit middling with it's large cast and rather crazy, gory and complex plot but with some great plot twists as a result (and meta-wise tries to redeem Chaos;Head's mixed to negative reception by righting wrongs using it as a foundation), heck LA will give the anime's ambiguous ending as pass as it gave a HUGE sacrifice from it's main protagonist in similarity to Okabe from Steins;Gate, but Silent Sky pretty much gave it's definitive ending that Chaos;Child needed.
ChäoS;Child: Silent Sky gives us the True Ending and really as much as it's of a bittersweet ending as the anime series, not all True Endings NEEDS to be happy and from the Science Adventure series, even more so.
