I see lots of people a bit, or very, confused about the ending, so major spoilers ahead as I make sense of it for you.
· · · · Borderland is a purgatory between life and death. When the "fireworks" hit in the real world before being sent to Borderland, those were actually meteorites. Everyone in the surrounding area of Shibuya then entered the purgatory state of Borderland where they played a series of games to fight to live -- just as their bodies in the real world were fighting to survive.
If people died in the Borderland games, that means their body didn't survive the meteorite crash, and they died in the wreckage. Those who made it through the games were presented with the choice to stay or go back. Those who stayed, died, and those who went back, woke up. This is why Arisu's friends didn't make it, but why people like Usagi, Aguni, Kuina etc. All survived and woke up.
In the manga, the Joker is a ferryman. He ushers people through life and death. In a game of cards, a Joker is also a wild card. This was likely a little nod from the ferryman to say that they survived Borderland, but now their last game to survive is life itself. Life is a wild card. The rules, like the games in Borderland, are simple, but the game is no less daunting. Things can happen you may not expect.
That's all. Hope it helps.
· · · · Borderland is a purgatory between life and death. When the "fireworks" hit in the real world before being sent to Borderland, those were actually meteorites. Everyone in the surrounding area of Shibuya then entered the purgatory state of Borderland where they played a series of games to fight to live -- just as their bodies in the real world were fighting to survive.
If people died in the Borderland games, that means their body didn't survive the meteorite crash, and they died in the wreckage. Those who made it through the games were presented with the choice to stay or go back. Those who stayed, died, and those who went back, woke up. This is why Arisu's friends didn't make it, but why people like Usagi, Aguni, Kuina etc. All survived and woke up.
In the manga, the Joker is a ferryman. He ushers people through life and death. In a game of cards, a Joker is also a wild card. This was likely a little nod from the ferryman to say that they survived Borderland, but now their last game to survive is life itself. Life is a wild card. The rules, like the games in Borderland, are simple, but the game is no less daunting. Things can happen you may not expect.
That's all. Hope it helps.