Bad acting, specially Superman's, OK CG, and another typical story of glowing artifacts that are used to destroy the world when put together. Like Marvel's infinity stones. Except Marvel did it slightly better.
I watched this after having watched the "dorama", the TV series. It's basically the same story, although obviously with not so many developments as in the TV series. It's strange and very funny. Somewhat disturbing, and somewhat romantic. I would recommend watching the "dorama" of the same name instead, but if you want a shorter version, go for this one. And if you loved the TV series, you'll like this one as well, even if it's basically the same story. Only the main character and his boss are the same actors. The rest is a different cast.
I resisted watching this movie because I thought it was for little kids, and because I was slightly disturbed by some trailers where I saw hundreds of fish with the same human face... But I finally watched it and it was better than I expect. I guess it's similar to Totoro, so a film for little kids, but that can be enjoyed by grown ups as well. Visually exciting, and with lots of magic. It has some message about the pollution of the ocean, but it doesn't really dig deep into that.