Okay, so it was indeed a game as suspected and it was Se Eun's parents who programmid it and the "AI" Jung Won who learned how to hack it.

I think episode showing Jung Won creating the game was her learning the harsh fate of everyone, and she's continually trying to end the game.

Also, Jung Won seems to be making sure Jae In remembers bits and pieces of the previous games. And in the finale episode, Jae In remembers everything from the previous one, including when she was awakened by Se Eun's parents.

The real question here is this: Did See Eun's mother reprogrammed Jung Won?

When the game reset, Jung Won was sitting far from Jae In. Also, Jung Won looks at Jae In with contempt.

I'm highly suspecting Se Eun's mother changed Jung Won (the AI) and now Jae In will be the one who will suffer the most since she volunteered to take responsibility.

I think that's what She Eun's mother did, she reprogrammed Jung Won to "think" that Jae In is the primary person responsible. Hence, Jung Won was looking at Jae In with contempt.

Even moreso, Jae In remembering everything is an additional layer of "punishment". She will be the only one who will remember the pain, as Se Eun's mother wanted.