This film sounds fascinating.

I thought it was amazing and it came and went from theaters inside of a week. I don't argue that it's flawed, but it does the sea and storytelling so well. One of the reasons I love Byzantium so much is that, on top of a mythos of vampirism I'd never seen before (see here), it gets exactly right the balance of the mundane and the fantastic that Ondine slightly fumbles. But Ondine has selkies, and those are still rare onscreen.