Heartwarming: Cave Story

  • The good ending.
  • Getting the Iron Bond.
    • Quote and Curly's past for that matter. Two adventurous robot best friends working together to stop the Doctor, in opposition to the army of Killer Robots.
  • In a meta way: the Hermit Gunsmith telling you it's a joy to create when people use his creations to the utmost. Given that Pixel created Cave Story all by himself as a labor love, it's not a stretch to imagine this is an Author Avatar speaking, about all the enjoyment fans get out of his game.