Heartwarming / Eternal Fighter Zero

• Anyone familiar with AIR surely knows that Misuzu dies at the end, and she was unfairly reduced to Memetic Loser status because of this; so, seeing her in this game, happy and alive once again will make you feel happy for her. And for this same reason, you will also feel happy for Kanna (If you can pass over her SNK Boss status.)
  • And for this very same reason, fans of Kanon will feel happy for Makoto.
• It's already listed as a funny moment, but Akiko's Final Memory can be counted as well: the fact that some girls are still terrified about the idea of tasting her "Special Jam" will surely warm your heart. Yeah, they're powerful and capable fighters, but they're also young, innocent girls. The most notable examples are Ayu, Makoto, and of course, Nayuki, who previously had experience with the jam.
• In AIR, Kano, Minagi and Yukito are Demoted to Extra, and never referenced again; so, seeing them fighting is refreshing, as they were given a second chance to shine: Kano is a powerful user of elemental magic, Minagi weaponizes her rice tickets and fights on par with her friend Michiru, and no matter Yukito is just an Assist Character, seeing him helping Misuzu in battle is both awesome and heartwarming (What actually happens is that Sora materializes as Yukito, but still...)
• In Kanon, Mai was a quiet and serious Emotionless Girl, and arguably the one who would have needed more therapy than the others; here in EFZ, she's a calm yet powerful Iaijutsu Practitioner, has a small ghost girl accompanying her, speaks a lot more (If her winquotes are any clue), and she even serves as a Warrior Therapist for other characters. So, it's safe to affirm that Mai Took a Level in Cheerfulness, and is actually enjoying herself.
• And the same can be said about Sayuri. In Kanon she appeared as a cheerful girl, but her smiling and giggling only actually concealed her true pain, in EFZ, she seems genuinely happy with her powers and fighting skills resembling those of a Magical Girl (With a few of Rugal thrown into the mix), to the point that, like the other girls, she's probably enjoying herself as well.
• Misuzu's Final Memory: if it connects, we are given a beautiful close-up of a pajama-clad Misuzu saying "Goal...", it gets better, if she manages to win the match with this move, she adds "Let the happy memories reside at the end..."; it's really a tender way to win a fight.
  • Even better, the fuzzy feeling of this instance are stronger if you have in mind Misuzu's winquote against Kanna, which counts as a possible reference to the implied Hope Spot that she will finally be happy in her next life, after succumbing to her curse, and dying.
  Misuzu: (On defeating Kanna) "The time has come. Everyone gave us 1000 years of hope. It's okay. I'll end it all on my own."
• A little case of Heartwarming in Hindsight: Kano-rin, you want to be able to use magic, don't you? There you go. Be happy.
• The whole game is already listed as a funny moment, but it doubles as a heartwarming moment: works by Key/Visual Arts are known for having really sad and depressing stories, to the point that here in TV Tropes, they warn readers to "bring tissues"; and the characters, specially the ones from AIR and Kanon, are known to have psychological issues, sad backstories, and in general, they have to go through a lot of pain and suffering before they earn their happy endings (which they do), so, you will feel happy for all of them (Even for Kanna, if you're familiar with her story, you don't mind her SNK Boss status), watching them fighting, being genuinely happy, and in general, doing something different feels like an additional bonus. If you have just completed the original novels or seen the anime versions, playing this game is like inviting a little of positivity back to your heart. No need to "bring tissues'' anymore.