There is also that flashback scene where Aika tells Mahiro that he would be the kind of person suited to date Yoshino. When Mahiro acts disturbed by the idea, she clarifies that she didn't mean it literally. But then adds that he should treat Yoshino well, because no matter what happens, he will remain by Mahiro's side.
Narm: When Hakaze reveals the date, and proves that she's stuck two years in the past, she doesn't specify the date, but does the common "XX AD," thing. Many fans wound up backtracking back through a particularly dramatic and suspenseful sequence.
In the anime, when Samon is thinking to himself, the background becomes a conspicuous purple, cheap "wee-oo, wee-oo" sound effects are played in the background, and Samon himself appears to be floating through space. It's difficult to take seriously. There's also the orgasmic gasping noises he makes when it seems like he's been out played. And his frequent Sword Planting quickly turns into an Overly Long Gag. Whether all this is supposed to be funny is hard to determine; it's very silly, but everything going on around him is dead serious.
Romantic Plot Tumor: The "who was Aika's boyfriend" question sometimes overtakes the whole saving the world issue, and even after The Reveal, Love Triangle elements take its place despite the hypoteneuse being dead for more than a year.
Take That, Scrappy!: Anyone who didn't like Hakaze from the beginning, or no longer liked her after she developed feelings for Yoshino, get a cathartic moment when Aika gives her a Megaton Punch for making Yoshino cry.