I don't think I'm smart enough to understand this manga. I don't understand why the eyes get like that, I don't understand the weird brainwashing mind control, I don't understand how the water works or how the people transforming works or how Reiko and the mermaid never banged. It's just too highbrow for me.
That said, it's incredibly atmospheric and I like it a lot. Maybe when it's finished and I reread it, I'll understand it better. The eyes are really freaky though.