I think three things motivate the player to continue playing the Danganronpa games; firstly the desire to “win”, and see the villains defeated and the survivors escape. Secondly, the morbid curiosity of detective fiction, the desire to see who dies and how those mysteries occur. And thirdly, the – in this case – equally morbid desire to see justice done for those murders. Ordinarily the pursuit of justice in detective fiction is not, per se, a perverse act to desire; the police intercede, or the detective pursues the crook, and they are sent to court and tried and that is that. But Danganronpa makes the act of justice into its own grotesque game that culminates in a parodic execution after the class become in turn judge and jury. The extreme, horror-movie tone of the executions – death by piano-shaped iron maiden, by fairground wheel of death, by baseballs, and so on – is just as memorable as the resolution of the mysteries and I would argue a driving factor in the game’s bizarre, horrific entertainment.
This article contains detailed discussion of the plot of Danganronpa V3, as well as Prey (2017)
In a lot of computer games, moral choices can be reduced to personality tests; they may be interesting dilemmas, but my enduring memory of games even as enjoyable as Mass Effect and Dragon Age is the choices still led you, eventually, to a fight or not a fight and a vaguely equivalent reward. This is not inherently a bad thing, the games still had memorable character moments, and generally hold up well as stories. Even something like The Witcher 3, which does not simply fall into good/bad decisions, generally has a lot of situations where the options are bad/worse and you as a player are not quite sure what will be worse (because the people the characters interact with are irrational, bigoted or stupid). But, nevertheless, it is not for no reason that moral decisions in video games became typecast as “do a good thing for a small reward, or a bad thing for a possibly bigger reward and a fight”; idea like Mass Effect‘s Renegade and Paragon points provided clear mechanical incentives for making choices that were often empathy versus utilitarianism. Bioshock was probably the weakest example of all; there, moral choice was “do you murder someone who looks innocent for immediate fiscal reward, or spare them for a larger reward later”. Hardly an interesting dilemma and almost a purely mechanical one.