The new trailer came out last week and despite being perhaps just a bit overdramatic, it sets up the stakes for what we expect to see in a Zero Escape game, though not why those events are happening (which have turned out to be different in every game).
The Zero Escape series features an unusual combination of visual novel and an escape room gameplay. Most of the story is told through narration and dialogue where the player has no control aside from making critical decisions. (In Zero Time Dilemma all dialogue is supposed to be voiced now, for less reading.) Then the player assumes control of the protagonist for the escape room segments where they have to explore a room and solve puzzles in order to find a way out. Anyone who's played a live version of an escape room game knows how these work.
As usual, Zero Time Dilemma features a case of nine characters trapped in a sadistic game where they have to make life and death decisions, many of which have consequences on the branching story.
New this time around though is that some of the consequences will be random. The example given at the latest presentation has the player deciding whether or not to shoot a gun secured at the temple of a trapped character. If they do not, a second character will definitely die. If they do, the first character has a 50-50 chance of getting shot in the head based on the number of loaded bullets. So the player could get lucky and have two survivors, get unlucky and have one, or choose not to involve luck at all and definitely lose one. The player is given ten seconds to decide.
Also new this time around is that the nine characters lose their memories after 90 minutes (the story being broken up into several segments) so that things can happen that the player has no clue about or how much time has passed. For instance, the nine characters are broken up into groups of three, and the player could wake up with only two characters with no idea how they lost one.
I'm pretty sure Zero Time Dilemma will follow a non-linear form of storytelling like Virtue's Last Reward where everything only comes together once the player has enough information regardless of what order they got it in. (And that would lean heavily on what Sigma and Phi bring to the table after the events of the last game.) Though it hasn't been specified that the game would play out this way, I think it would be a head trip if the story fragments are actually experienced out of order, but the player is unable to distinguish that right away due to lack of information.
Either way, it'll definitely be interesting!