Heartwarming / Summer Wars

  • The fact that Oz's virtual guardians are names after John Lennon and Yoko Ono, a couple who's public image symbolized love and optimism. It's the cutest thing in the world.
  • Natsuki's whole reason for bringing Kenji? She thinks this might be Sakae's last summer and wanted Sakae to not be worried about her and how she was doing and knew her seeming to have a fiance would help with that. She just wanted Granny Sakae to be happy.
  • That scene when Kenji is first introduced to Sakae. The scene and subsequent material implies Sakae wasn't fooled for a minute by Natsuki's lie. Yet she still lets Kenji stay for the celebration, almost certainly due to his sincere answer of 'Yes' when asked if he was willing to die for Natsuki. Given what she says about ever being wrong about who will benefit the family, Sakae sees something in Kenji that the shy kid doesn't see in himself. And before the movie ends, her assessment is proved completely accurate.
  • When Natsuki loses the 49th round and doesn't have enough accounts to continue the game and all seems lost, a boy from Germany shows up to offer his account. Within seconds, people from around the globe offer their accounts so Natsuki can defeat Love Machine. According to Sakuma, it was about 13.837% of OZ's total subscribers, over 150 million accounts. Cue Tears of Joy.
    "Please protect our families."
  • Sakae's final conversation with Kenji before her death. What made it even more bittersweet is the fact that she had faith in him the whole time.
  • The scene where Natsuki asks Kenji to hold her and make "them" stop. Just as he's about to ask what she means, Natsuki extends her hand to him and begins to cry. The dam breaks, the moment he touches her hand. Also doubles as a Tear Jerker.
  • When using the "Flood the Castle" tactic on Love Machine, there is an adorable shot of Kazuma holding his toddler cousin Kana on his lap. Just by seeing it, you know Kazuma going to be a great big brother when the time comes.
  • Even though Shota taking ice away from the super computer was a big mistake, it was still very sweet of him to do so because he wanted to keep Granny Sakae's corpse cool.
  • Seeing Wabisuke's reaction to Sakae's death was pretty touching. After Natsuki calls him with the news, he Drives Like Crazy back to the house, pulling up in a wrecked and dented car, screaming if it was true.
  • The reading of Sakae's will combines this with a good Tear Jerker.
    • When Wabisuke showed up, the first thing she asks him is, "Have you had anything to eat?" According to her will, the worst things are being hungry and being lonely. She's glad that he's back so she can fix both.
  • When the missile falls just short of its path, that moment when the entire family shields each other in one huge embrace.
  • The ending scene:
    • That kiss.
    • It's an Everybody Laughs Ending- even granny Sakae's portrait changes to show that famous toothless grin we saw her make before passing on.
    • When the family finishes singing to Granny Sakae's picture at her funeral, you can hear Kenji say, "Happy birthday! Thank you for believing in me!" as the family cheers.
  • In the manga, the extra/epilogue when Natsuki reveals that she wanted to get into Tokyo U because Kenji applied to go to Tokyo U as well.