JohnFreeman said: Damn my eyes! T_T The entire manga should be in the "Soul-Crushung Depressing" pool
Can't say it was depressing actually, the robot (rin) finally obtained her kokoro, the same thing that the professor (len) was making her to make her a real miracle. The moment she spent "alive" outlasted the hundred years that she remained alone, and to finally pour her heart out to the one she loved was the most gratifying moment of her life. She lived happily in song and died happily to finally be able to give her heart to him before he died.