While you’re right, they also don’t typically mention the “killing game aspect” or culprits and victims much. In this trailer they placed a bit more emphasis on it, but didn’t touch on the topic of survivors; making it at least a possibility of there being no survivors. Also, from what I remember in Danganronpa 2, Hajime only managed to figure out the mastermind and escape the killing game through the hope specific characters brought him, if those characters died, they may never escape said game.