We can't say for sure if the new 3DS/PlayStation Vita game from the 999 team is meant to be a true sequel to 999 but, as you'll see in this trailer, "Extreme Escape Adventure: Good People Die" (as it's being unofficially translated online) is definitely related.
The "Nonary Game" and its associated watches -- each one bearing a number that is assigned to one of the unwitting participants -- return, in a new blue "Ambidex Edition." Even Zero, the mysterious, masked perpetrator of 999's deathtrap, appears in the trailer.
New additions include 3D (meaning polygonal) character designs in-game, instead of only hand-drawn character portraits. This group of dupes is made up of all new people, as well. There's also some kind of creepy rabbit.