It's a bit of a gray area. While not a typical short story, the Allegory of the Cave uses fictional scenarios and a sequential presentation to communicate its message, which shares some characteristics of a short story.
5 Mile Cave is most likely fictional. Usually, such names for caves in stories or tales are made up to add an element of mystery and adventure rather than being based on real events.
Sure. The true ending of Cave Story exists and is achievable by fulfilling specific conditions and completing certain tasks within the game. It offers a satisfying conclusion to the story.
Cave Story is a unique game with a compelling storyline and challenging levels. It has charming pixel graphics and various enemies and bosses to overcome.