For emotional impact, I think this game has few contenders for top spot among AVNs. The sensitivity and maturity of the writing, the natural sounding dialogue, the colours, framing and facial expressions of the renders are just some of the things I absolutely love about this game.
If you are trying this game for the first time now that the second chapter has been released, please, please bear in mind that this is not a porn game. Don't go into it expecting that. You are doing both yourself and the game a disservice if you do. Nothing wrong with those games, but this ain't it.
This is a story of three (more than that actually) people trying to cope with their lives, with loneliness, connecting with others, friendships and their own past. And that story is also what makes this one of the best AVNs I've played.