about Mermaid

 I was absent but my friend told me that there's homework. I genuinely appreciate it.

The Main Character

 I assume that the main character of this animation is the boy who met (or just saw?) the mermaid. That is just because the story mainly continues with this man. 

What the author wants to tell

 This work presumably implies importance connected to freedom of expression. When the author, Teduka Osamu was small, it was before the end of WW2, so freedom of expression was not fully secured. In that situation, it could be said that there were some hard times for him to express what he really thinks, like the boy in the video. This animation was made in 1964, but I think he wanted to tell us about it and to think about it again even though freedom of expression is now fully guaranteed.

The end of the video

I think the last part means too much restriction or oppression can kill a person. I think it's a really common situation and that can happen in every situation like oppression from parents or teachers, too much work or even too much pressure from others. In the scene that the boy went away in the sea with the mermaid, it looks as though he went away quite calmly because he was there with what he believed, so i think it’s important to respect what people think and not to oppress what many people say and think. It's clear that it also connects to more diverse imagination and creativity.