1. I think that the videos were a unique way of teaching children about the nuclear plant. Just the teacher has to stress that it is not about a real child and show that Fukushima was destroyed by this. Either way it's very hard to teach little kids about serious subjects, so this might be the best way.
2. I did think the video was a little immature for a serious problem so I would try not to use too much of that dirty language.
3. I thought that the American version was more immature in the way that it was too excessive and exaggerated things that were dirty and disgusting.
4. I wouldn't like to put either of them in my room as a poster but if I had to I would choose Genpatsu-kun just for the reason that he's much normal and human than the cyborg type Nuclear boy.