Narm: Through the Years and Far Away to some, thanks to the Engrish.
Spiritual Adaptation: This is perhaps one of the best adaptation of Joe Halderman's The Forever War in existence, although some differences (e.g. the genders are flipped) exist. Even the aliens are called Tarsians.
Stoic Woobie: Noboru narrates with subdued unhappiness that he worries about "becoming someone who only waits for Mikako's mail." When he receives the message telling him that she's now eight lightyears away, he resolves himself to close off his heart and move on - but as we see at the end of the film, he doesn't succeed in doing so.
Wangst: Noboru falls into a depression when he feels that he's been idle for too long, but near the film's end, it's revealed he's also joined the armed forces to both be actively engaged in defending their planet, in addition to the prospect of reuniting with Mikako.
The Woobie: Mikako, who does her best to keep up a positive attitude about her increasing distance from Noboru only to finally break down sobbing on Agartha.