Atmosphere: 10/10. It made me feel sad. Not a 'crying sad', but more of a remorse sad. It made me think of the stupid things I've done-- particularly to other people. I know how I feel, but only another and God can know how oneself feels. I hope I shouldn't make life any worse for any other people (past what I have already done), no matter how the other person truly feels.
Mechanics: 10/10. The game is simple and, no matter how it's played, the character ends up alone. I suppose this ultimately digs into the almost cliche saying of "'Tis better to have loved and lost / Than never to have loved at all."
Entertainment: 10/10. I played this game not knowing the outcome, which seems most parallel to real life. As the dot neared the dark ending to a slow game, my chances of acceptance-- finding one other dot who empathized or even cared-- became lower and yet my hope for the dot became stronger. Sitting alone in a room, drinking a crappy off-brand cola with my air conditioner blowing and a summer of potential before me, I was crushed when my dot-- whom I had lead through this world that was foreign to both it and I-- had not encountered nor maintained a single companion.
Overall, a 100% thumbs up. It seems almost ironic that most of this review was about my existential reaction, but, hey, isn't that the point of an "art game?"
(P.S. - I don't think you could have chosen any more fitting music.)