The ending was literally "it was all a dream" IMO it's kinda dumb. I was trolling in the game about "spoiling the ending" - a bunch of people on the internet had fan theories when it was a manga about how it was going to end and a lot of those ended up being better than the actual ending (eg. it's aliens or something). I used that in my game to fake-spoil the ending with a better ending (wrote some shit about aliens). So the actual show (with ending) explained is this: there was a catastrophic event (meteor) and a bunch of people were injured and went into a coma in the hospital or something. then they all have a shared coma dream in which they're competing in this game (what we saw for most of the show). The people who hang on and make it through the show are the ones that survive in real life and wake up from the coma. The ones who give up or die in the games die in real life and never wake up from the coma. Then there's some little hint around whether they actually remember each other/are destined to meet each other after the dream or something. In all I think it's a fun show but kind of unsatisfying ending.