999's remake ending explained

So, the twist is that you were watching the past (or present?) and the present (or future?) at the same time, each in every screen, the entire game.

Akane was seeing everything that future-Junpei was doing all the time, in parallel; it's not that she could see all of the future, she was just watching Junpei "in real time" 9 years later, culminating with the last incinerator puzzle, in which she needed his help to complete it.

If Junpei wasn't there in the future to help her, she would die, so after she survived thanks to future Junpei, she needed to make sure that, 9 years later, the events occurred exactly as she saw them, so she prepared the Nonary game with the help of Santa and other people. It's a classic bootstrap paradox: if she didn't saw Junpei, she couldn't save herself, but she only saw Junpei because she set him and the others up to save herself, and she only could do that if she was saved, ad infinitum. Boohoohoo.

The thing is... in this remake, it's very likely you'd only see the ADV screen, aka JUNPEI vision, aka the DS's top screen (and just a tiny bit of the novel screen when the game forces you). In the original version, you'd see the characters' dialogue at the top screen and the narration at the bottom one, all the time. That way of playing makes the twist a lot more powerful in my opinion, not to mention the upside-down sudoku. Uchikoshi, the series' writer, even came up with the dual-screen-twist first, and then made this game around that.

But I get there wasn't a better option to maintain even a little bit of that important plot device in this version :c