It is not an all happy go lucky anime despite the fact that it's more colourfull than less dark or cruel anime(like darker than black or steins; gate).
It really works on its characters and their feelings and backgrounds, so if you are not prepared to think a bit more deep about feelings and getting in the shoes of someone then don't watch it!
Although it is a rather sensitive anime if you don't like shocking events like death-and even massive one- then don't watch it!
I personally saw a video and like Nezumi that is why I started the anime!
