Rain Code is the perfect spiritual successor to Danganronpa. By the end, the game has you emotionally invested in it. It's also far more replayable than Danganronpa, with collectables that are actually worth finding and a great cast that you'll definitely want to see more of.
The graphics are 10/10, with almost all cutscenes (which are fully animated and scattered all through the game, unlike Danganronpa) looking fantastic. However, besides the cutscenes, the animations are somewhat lackluster, but if that doesn't bother you, this game still has a great story and is a visual treat!
Another thing is how this game is set up. It is a far better introduction to the mystery and visual novel genre than Danganronpa, so first time players of this genre will have a better experience.
Finally, despite me saying "Danganronpa" so much, Rain Code is an all new IP and has a very different feel to it than it's predecessor. It's still a great game for Danganronpa fans, visual novel fans, and newcomers.
If you love mystery visual novels, this game is a must.