Wow, I’m so glad that you were able to play it! I’m really happy to see you enjoyed it.
As for the origin of the ghost. It’s a pity that part of the story only appears in the news from Day 1. But if you read it, you’ll probably understand what kind of person he was.
And if you really want to play again, there’s a text document in the same folder as the game called “For those who wish to play a second time.” It explains how you can experience the game once more.