Harmony has quite a number of issues that make it less engaging of a sci-fi title with a similar premise as it like Psycho-Pass. First would be its choice of main character in the form of Tuan. Psycho-Pass featured its female lead Akane confronting the realities of the so-called utopian world she lives in and these experiences shaping up her character's beliefs and mentality as episodes progress. On the other hand, Tuan's character is difficult enough to even establish a connection with as she still stays the same moody and bitter person she was from the start of the movie with her disgust of the world she lives in and still stays as such, even with the revelations she comes across with the power structure that runs her world.
The second problem that comes up with Harmony is its heavy dependency on character conversations to advance its plot. Some might take offense to this as an issue as there can be titles like .hack//SIGN that effectively pull such use of this storytelling device to further explore its world, develop its characters, and unveil more elements to its plot. But whereas the use of said character conversations in .hack//SIGN are balanced out by exploring character chemistry and the world of its series, Harmony is heavily dependent on character conversations for plot advancement as such where a number of relevant characters in the film exist only to infodump Tuan with information needed to move on to the next point of the film's plot and said characters get little fleshing out to be anything more than flimsy plot devices.
The third and major problem that comes into play with the film is its very plot. The first half-hour of the film is focused on establishing the bond between Tuan and her two friends to show what drove the three of them to defy the established societal order of their world and the remainder explores her taking on the case involving the mass suicides. Outside of the mentioned issues I highlighted from earlier, it felt like whoever wrote up the story and characters for Harmony approached the matter from the eyes of an angsty and nihilistic teenager as the film plunged too deeply into exploring the dark side of its world without realistically considering the ramifications for what would happen if its future went down the tubes if its worst-case scenario played out.
Overall, Harmony makes a failed effort at trying to have something deep to say regarding its premise thanks to its unlikable lead character, being too dependent on character conversations and infodumping to advance its plot, and said plot lacking a deep and cohesive enough narrative to be engaging to its viewers. It's a title I wouldn't waste any time on tracking down or even rewatching a second time.
