I like most of the plot structure of The Devil's Backbone. It is a powerful film that does a good job of showing the struggle of these orphans during the Spanish Civil War, and the struggles of those who are running the orphanage. There are a number of endearing characters, and their frustrations felt quite genuine. It was easy to sympathize with them, and I found myself forgiving some of their misdeeds because of the awful situation that trapped them in this place. I could even see where the villain was coming from, and how he came to be this man (even if he was a bit over-the-top at times.) The kids were mostly strong actors, and Fernando Tielve in particular gave an emotional performance that I enjoyed as the new boy to the orphanage. Likewise, it's easy to like Federico Luppi as the loving caretaker and doctor in the orphanage. There are also some solid visual effects and makeup work that made the ghost look creepy.
There's just one thing that stood out to me as a negative when watching The Devil's Backbone. I cannot understand why this is a ghost story. There is an intriguing drama going on with perfectly normal characters, and then there's a ghost. It is tacked on in the weirdest way, and never once feels like a natural part of the story. It made me think Guillermo del Toro was just testing the waters for what he would later do much more effectively in Pan's Labyrinth. That film blended the magical world into the story seamlessly, but The Devil's Backbone struggled to weave it together in a cohesive fashion. I've never been all that fond of ghost stories in the first place, so to see one grafted on like this lessened my enjoyment. I didn't even feel the scares were all that effective. I'm not sure if they were intending to make the film have a horror feel, but I could tell that there was nothing to fear from the ghost from the beginning. I still think The Devil's Backbone is an interesting film, and I appreciated most of the plot, I only wish it stuck to that main story and left the supernatural out.