SDR2 is everything a sequel should be: it borrows the ideas from the first game, it adds some of its own and combines everything with a lot of self-irony to create a mix that is always entertaining.
I could end the post here
- Story: SDR2 could be seen as a visual novel (with lots of gameplay), so of course the plot is a primary concern. Well, fear not, because the only downside I can think of is actually related to the game's mechanics. And with that I mean how every chapter is basically the same as far as structure is regarded: Daily life -> Deadly life -> Trial -> Repeat. Basically you know from the start that someone's going to die over and over again, but hey, there's little the developers could have done for that, if anything at all. The things they could do right, they did, because the plot twists and the crimes very rarely let you down.
- Style: As I kinda mentioned above, SDR2 is full of self-irony and references, both to its own brand and to other famous stuff. Not only this, the concept of "breaking the fourth wall" is redefined, especially in the last chapter of the game (which, by the way, is pure genius). This is especially - but not only - Monokuma's merit. The guy's a nasty bastard but from the point of view of the gamer he's simply brilliant. Bravo to the developers.
- Graphics: Who even cares about this, let's go on.
- Music: While not being phenomenal it's pretty good, especially in-game, so this passes too.
- Longevity: If you're crazy like me you'll spend every day of the week to clear a chapter and you'll still want more.
- Gameplay: Simply catchy. The daily life is probably the weakest part, but it lets you know the characters better and they deserve it; the investigation and trial parts are simply awesome and you'll have serious troubles putting down the console when playing those.
tl;dr Play it.