Where to begin? I had an idea what to expect and this movie delivered that and more. It's not a horror film as much as a psychological thriller. It focuses on ethics and human behavior and how it can go so wrong. While some of the storyline seemed unbelievable, it mostly made sense in a twisted sort of way.
The actors did a fine job, especially Delphine Chaneac, who plays the creature Dren. She is far more human than the humans, though. The questionable ethics go beyond splicing human DNA with animals and delves into the area of child abuse. Dren turns on her human 'parents,' not so much due to her animal DNA as due to the physical and mental abuse she endures.
In an interview with producer Guillermo del Toro, he said that when he read the script, there was a line he would never cross in a film. This movie crosses that line twice in a sexual manner guaranteed to shock. For that reason alone, this movie is not only inappropriate for children but for anyone under the age of 18.
The special effects are incredible. I never once questioned Dren was real.
If you're seeking summer movie enjoyment, this is not the film for you. It will get under your skin. The characters and storyline are well developed, but it doesn't prompt repeat viewings. The movie is of quality and well done, but I will stop just short of recommending it.