The initial idea was good, a man being a young again, but he's aspect do not change but the people see he more young. Superman 2.0? I cannot do spoilers, so I cannot talk about the development.
About the animation, I was waiting a animation like Shigatsu wa Kimi no Uso, Tonari no Kaibutsu-kun, Orange, Isshukan Friends... This animation is bad for an anime like this, and when the seiyuu stops talk, the character still moving the mouth a few seconds. Small details like this are important.
The only good thing about the song are the endings. After see ReLIFE, I hate the piano.
