Basically what you are going to see is a movie about tragedy and dark subjects disgused as a fantasy one, which in my opinion is a better and clever way to do it than just make a drama movie and trying to replicate what happened in real life.
I understand that if you are not informed about the events that inspired this movie, especially if you are not from Guatemala you won't be able to fully appreciate this movie and understand some details that the movie shows. But I also understand (like with every other movie out there) that even if you are guatemalan or you know the real events behind this movie that does not mean that you have to like it.
That being said, I want to say that this movie is good, I really like it, it's not a masterpiece but definitely a decent movie. If you can't decide whether to watch this movie or not, I recommend you to watch it, you won't regret it.
Things I didn't like about the movie: Sometimes the dialogues are at a low volume so you can't really hear what they're saying unless you turn up the volume. And another thing that i felt it could have been better was the ending, I think it was a bit rushed.