I'm gonna talk with spoilers in this, so you are warned.

AI: The Somnium Files - Nirvana Initiative, is a good game, it has a bunch of good new characters, and a story that if you connected all, you'll see how good it is, but despites its good points. It has a weaknesses, the treating of the old characters is one of them specially Date, I mean the game follows the real ending of the first one and in that ending Date recovered his body but in AINI Date uses a silicone mask an excuse to remain his old face, and I'm not talking just about superficial things like that, all his character development doesn't exist anymore, it's almost like he wasn't past for all. Anyway, the protagonist od this game are good, specially Ryuki his dinamic with Tama is similar to the relationship of Date and Aiba, but Ryuki has a gold heart, as for Mizuki or I should say Mizukis with Aiba, they don´t have the same spark, they are kind of boring, I swear that despite I love the character of Mizuki, there was parts of the game that I wished to be back Ryuki cause the chemistry with Tama and all his character were more interesting. Even so I love all the game, It was good back to the world of Somnium Files and I hope the possible future sequels improve the weak aspects of this game and take all their strengths.